Thanks guys.
Anthony, I think you will do great with a mono Lu. It's not cheap though, by the time you get filter wheel + filters. Plus it's more effort in both capture and processing. So you need to decide if it's right for you.
The DMK has a ROI feature but I believe it SOFTWARE ROI and not hardware - so I don't think it increases the framerate because it still has to pull the whole frame down before applying the ROI feature.
That's one of the benefits of the LU.
Secondly, my tracking isn't accurate enough to be able to make use of an ROI feature unfortunately. The planet moves all about the 640x480 FOV during my 2 minute capture
Have you had a look at the new SkyNYX (or whatever they're called) cameras? Damian Peach is selling his Infinity 2-1 camera on Astromart cause he's now got this new one, he reckons it's even more sensitive with less noise than the previous one. They're not cheap though.