Sorry I didn't explain video astro well. I take short 10-30sec exposures on a GOTO mount (unguided) and stack them live while viewing. The purpose is near-live colour viewing of DSOs - not photography.
Last night I used EOS Utilities to take 30sec exposures @ ISO1600. While doing this I stack them while viewing in Astrotoaster. The shot below was saved directly from Astrotoaster, no post processing.
So poor man's live astrophotography
Below is Lagoon + Trifid 16x30sec subs, taken with a 550D I modded (removed IR filter, but there's a bit of gunk on the sensor I'll have to clean)