You probably know by now
but iMovie works just fine on the mini, as long as you have a good way to get your video onto the mini's camera roll.
Depending on how you're taking the video, you may want to get the USB camera connection kit. I use that to get pics/video from my iPhone (4s) onto my mini. It would probably work for other video sources as well. It will put the video in the mini's camera roll right where you need it.
Good call on the 32GB for this reason, btw!
And good call on picking up the mini now -- who knows if the "2" will be out even in 6 months, or if it will be retina.
Regards,
Tom