I would not even attempt to run TVHeadEnd on a Raspberry Pi, how would you install tuner cards? I know there are USB tuners but I have heard that some of them have short life expectancies due to overheating, and anyway I would not try to pass significant amounts of data through the Raspberry Pi's USB port. That might work for people who only want to use one or two tuners and watch only low bitrate signals, but I sure wouldn't try it if you want to record multiple high definition signals at the same time. Not saying anyone else should or shouldn't, just that I wouldn't.
But as for the other guy that maintains a media_build system, who is that, and does he have a page explaining his project? And more importantly, do his TBS open source drivers support the TBS6905 and similar newer tuners? The last time I was looking at an open source TBS driver, my impression was that they support the older tuner cards just fine but not the newer ones. But if you can point me in the right direction, and assuming he has some contact information, I'd like to find out if support for the newer tuners have been added. Open source tuner drivers are a great idea, particularly if they improve upon the standard drivers from the manufacturer, but if they don't support your tuner card then you still can't use them. And I understand that these guys may simply not have access to the newer cards; it's not like TBS in any way supports third party driver development, and I'm sure they don't send out engineering samples to the open source driver developers.
I have no idea what a "tool chain" or a "module for MIPS" is so your third paragraph pretty much went right over my head. However I'm surprised to read that someone could run a Prof 7500 on an AzBox, because I thought an AzBox was just a fairly expensive receiver that had the unique distinction (among standalone receivers) of being able to receive and display 4:2:2 feeds in real time, and from what I read it doesn't do much else particularly well. The impression I got was that it was kind of a single-trick pony, so I'm a bit in awe of the fact that you could make it do that.
As for your last paragraph, in the first place the guy I mentioned never got booted off Rick's forum. I just said that Rick censored his posts or delayed them for a considerable period of time, so he gave up and moved on, because it's pretty hard to participate in discussions if everything you post is delayed by a day or so. Anyway I would not be so quick to assume he deserved anything because I've read similar complaints about American satellite forums in general; it seems like all of the major ones are run by hams, and they all have particular ideas about what should or should not be allowed. You can post things on Rick's that would be censored on SatelliteGuys and vise versa, and they don't always explain the particular things that will tick off a moderator. Also I have seen the accusation, and I believe this, that on most of the forums satellitedealers can write things that would get any regular user's post removed. I do know that guy is not into any kind of pirate or hacking crap, so that couldn't have been the problem. Anyway it is water under the bridge now, he wants nothing to do with that forum. My reason for staying out of that particular forum is that I just don't understand most of what they are writing about.
And I did not say that they don't help people. But there is help you can understand, and then there is help that is not really helpful because it all flies right over your head. If you try to help someone who knows little about Linux using the same language and minimal instructions you would use if they were a Linux guru, that's not helpful at all. I'm sure the people who offer that kind of help go to bed feeling good about themselves because they think they tried to help, but really they didn't, but I don't think they even realize that.
To give you an example of what I would love to see, there is a PBX (software telephone switch) program called PBX in a Flash, and what happens is you download an ISO file and burn it to a CD or DVD, or transfer it to a bootable memory stick, and then on the computer you want to install it on you boot from that media and it wipes and reformats the hard drive (it warns you first!) and then it installs the Linux operating system of your choice (I think you can choose Ubuntu or Scientific Linux), a firewall that is preconfigured, the Asterisk PBX program, the FreePBX GUI and configuration progroam for Asterisk, and various other software programs that assist in running a PBX or providing security. The big advantage is that after the install completes, everything works. You don't need to know how to set up Linux, it does it for you. You don't need to know how to install Asterisk or a firewall; it does all that for you. A half hour later you have fully functional PBX. Now I am not promoting that program, but I sure wish there was something like that for TVHeadEnd users, that perhaps would include the following:
Ubuntu Server (maybe Debian as a second choice) with whatever kernel hacks are necessary for the additional software to work
TVHeadEnd (NOT the OpenElec version, but it maybe should give you a choice which branch you want to install, such as the stable branch).
Third Party TBS drivers for the cards supported, and the stock TBS drivers for the cards only supported by TBS
Webmin (or something similar) for GUI based server configuration
A firewall that by default restricts access to devices on the same local network as the server
Help files that are actually understandable and show how to do common tasks.
And all the little extra addon utilities that can assist in tuning in a dish or tweaking the system for best performance.
Now I am under no illusion that anything like that is going to ever actually exist but that would be the ideal for people who are not Linux gurus. I don't think there are enough knowledgeable people in the hobby to create something like that. In a way it's a chicken and egg problem; if few people understand this stuff to begin with then even fewer would be capable of coming up with a distribution such as that, and I think it would be more than a one person job to maintain it.
Again I am not accusing people of not trying to be helpful. What I am saying is they have their own jargon and their own assumptions about what people already know, and if a user doesn't know the jargon and doesn't have the knowledge they think he has, then their best intentions to help won't really be helpful.