Certainly building my own small form factor system is something I can do nicely and for great value for $700-$1000 USD., but that would be a 100% investment to what would essentially be a dedicated gaming rig...
Excellent point about CPU thermals and overtaxing a MBP... something I'd hope Apple built in some safeguards for?
I didn't mention this above, but as my screen name suggests, I am also a Large Format Print Designer, by day and a dev at night, and although the rendering (CPU) tasks aren't as hardcore as video editing, I do have challenges being able to work from home on art that's huge in size and graphics, and even maybe the occasional FCP project.
So if they're not a good value for someone like me ( MBP user, space limited, not too price sensitive, not hardcore gamer ). Who are they designed for then? Especially if the economics just don't make sense, is it risky to invest in something that may suddenly loose support because no one uses them?
Sometimes as a Mac user I just don't feel the love from LTT...