mpegs are a delivery format, enf-of-the-road, not meant for further processing... nice for playback, bad for editing (don't store every frame...)
iMHD5/6 support import of mpeg2 - as on HDcamcorders (HiDef); needs some "hints" in the firewire stream; gets automatically converted to Apple Lossless Codec; and needs some "special setting" mpeg on tape… (has to do with b-, p- and i-frames...)
I don't expect support of miniDVDcamcorders - these gadgets are useless for a real edit experience, they're like that KodakBoxes, 90y ago... mpeg4 (recording format of some still-cams with movin'pic ability) is slightly supported via import thru iPhoto...
iM is a consumer product/FCP does support native mpeg2 edit, e.g. for ENG-harddisk recoders...
Apple likes quality - miniDV/HD-miniDV... now comes ADHD-DVD, but same dilemma...
first problem to solve is a disk-media for HDcontent/BluRay superdrives....