LCTs (landing craft, tank) would be very cool. Drop three or four tanks/trucks off on shore from a CV, giving our CV a much stronger ground assault role. LCTs would be even better if we had a Sherman.
A good site about LCTs, chairboy. A bit rough in presentation (MIDI music, eww), but lots of photos and good information.
http://ww2lct.org/Especially the "History" section.