are you just going to be bringing the hardware RAID live? is it going to be part of the exsisting box?
is it external? more info.
should not be to hard to 'ghost' the info from your software raid over to your hardware raid, then point the BIOS to the correct location. i would like to think that *nix is robust enough to do something like that. i have never tried, but in principle that should work.
if not, you may wish to bring a 2nd comp live for a short time, move all the data around there, then bring it live back to the system with the hardware RAID.