Problems:
- Money: We can't fund it, we're each funding our own other projects
- Team: We're super busy and don't have the time, we're also not super keen to work on an old game again when we're doing new stuff. So we'd have to find someone else to do the work, and pay them somehow.
- Publisher?: This might be a solution to both the above problems, and I get the occasional email from a publisher talking about porting the game to XBLA... but most of them seem pretty shady.
- Quality?: There'd be no point in doing it if the development team involved didn't care, or sucked and the port ended up being terrible.
So yeah, if you can solve all those problems we'd love to do it. 
Any idea how much the development will cost?
Sounds like a publisher would be best.
Perhaps I will see what I can find out about these "shady" publishers for you? What about seeking a publisher of your own? I could definatly help you there.
For the quality, your right about doing it it properly. I'm glad you care. If a trustworthy publisher could be found with a good reputation, then this shouldn't be a problem.