Short question:
Would it be possible, to record audio on 50D, by using a USB-Mic (MLV-Rec or H.264)?
If it's not possible right now - maybe it would be a good idea to develop something like this for the new firmware update?
I mean, the 50D is a really good video camera by using Magic Lantern Firmware (especially for it's low price), but the point for most people is the problem of missing audio recording functionality.