Ok, let's break down the requirements on a list as it appears the AzBox miniMe American Edition meets most of your requirements.
.....
- Stream it or otherwise make it available to computers on the local network.
The built-in web interface allows you to change and view a channel with computers on your local network via their web browser. A link is also provided to view the stream on VLC if desired. Sorry, no MythTV backend support yet at this time but I will add it on our list of enhancement requests. However, as the miniMe was designed to be a frontend and not a backend, this won't be a high priority item.
Well, the issue with that is that nowadays people want to view their content on multiple screens. If XBMC can receive the stream that would work too, provided that recorded programs (not just live streams) can also be accessed and viewed from other computers and devices. In fact I am really more concerned with the ability to watch recordings on other devices than live programming. MythTV just puts everything in a nice common interface, as does XBMC for that matter.
- Preferably can receive multiple streams (at least two) at once.
Multiple computers can view the channel stream at the same time but the maximum amount of clients depends on the channel's bitrate as each extra client adds a certain amount of CPU usage on the device. Once you have too many clients connected, the stream will start breaking up on all computers as the miniMe's processor can't keep up anymore. An interesting feature is that you are able to stream a channel on your computer and view a different channel on your TV at the same time if it's on the same MUX.
What I am really looking for is two independent tuners that can connect to two separate dishes aimed at different satellites, or different transponders on the same satellite. I personally can't think of any circumstance where I would want to watch two different programs from the same MUX at the same time. Receiving the very same stream on two different devices at the same time might be a possibility, though. But as I noted, recording is far more important - it needs to be able to record two different programs at the same time.
Other than the above, everything you mentioned sounds great. But there is one thing you didn't mention - the price! Maybe I am looking in the wrong place but I can only find those receivers at around $220. And in today's market that just seems too high for a single tuner model.
Consider, for example, that today I stumbled across the page for the Amiko Alien2. It appears that it will do most if not all of what the AzBox you mentioned will do, AND it has dual tuners, AND it sells for $214.99. They specifically state that it will stream live satellite to PC including 4:2:2. I don't know how it compares in quality to the AzBox, but from the feature list they appear to be very similar, and the price is similar, but you get dual tuners with the Amiko.
I haven't committed to any solution yet, but I am just saying that unless there is some source offering a much better deal on the AzBox miniMe than anything I found via a quick search, it's probably not something I would jump at, despite it meeting most of my other needs. I appreciate your post and I'm not completely discarding the idea that the miniMe could work as a partial solution, but basically I'd need two of them and even if I could get them for half price, they'd still be using double the power.
I probably shouldn't even mention the fact that while looking at that site I saw they are touting an upcoming new, very small single tuner box for $69 (pre-order price at one of their dealers, which shall remain nameless), but I am pretty sure that one will NOT do 4:2:2, and probably doesn't have some of the other features of the larger models either. And of course I have no idea how the quality of the two brands compare, nor the customer support. But I suspect we are going to see satellite boxes start to shrink in both size and price as newer chips come onto the market.