It's the encoding end you're going to run into the most difficulty finding. There are likely some software solutions which I believe have even been mentioned here before, but that necessitates what you've mentioned, installing a capable PC at one end. Software like Orb or that other one which I think starts with a "T" that Tony was looking at. You can also use SageTV. They may all require their own place-shifting software though, so you'll have to look more closely at them.

I don't know what codecs and protocols the Sling products use, but I'm fairly certain their platform is built to at least try and be robust and consistent. Whle also not pissing off the broadcast and content industry too much (ie. the restriction on placeshifting client connections).

With regards to VLC, I've used it simply to stream a video file over a network share on my own LAN and it seems to suck at that. It plays back local files well enough, but even over a rather fast LAN it chokes badly. Quicktime always seems to work fine, so I imagine it's all in the buffering code.