@FieldMarshalGames:
My initial thought is
Cost: 4
AT: NA
DF: NA
MV: 2
Acts like a Naval transport but on land. Can move 2 INF OR 1 INF - 1 ART 2 spaces.
Can not be taken as a casualty
Is automatically destroyed if left alone and attacked by enemy unit.
I think that you pretty close with this one however I think this variation would be better:
Cost: 2
AT: NA
DF: NA
MV: 2
Can carry 1 infantry (or elite infantry) and 1 other land unit.
Must be taken last as the casulity in a battle.
Why the cost of 2? A couple reasons. First we already have a lot of 4 ipc units.
Second and more importantly difference between an infantry and mechanized infantry is 1 IPC and for that the mech can move an additional space, can blitz with tanks, and loses the abiliy to be considered an infantry for transporttation purposes. That tells me that the abiltiy to move an additional space for land units costs 1 IPC. Since the truck transports 2 units 2 spaces and have no other abilities the cost should be 2.
Third the lower cost would encourage players to purchase more artillery since they could be sent to the front quickly unlike most games I see.
The downside is that the cost of 2 may be low enough to make mechanized infantry obsolete. At the very least, a compromise of 3 IPCs should be considered.
Thanks for listening.