Alzrius said:
I'd say just give him a few levels in the Controller class. You'll have to slightly adjust the stats for his mechamorph companions, but they'd still fit into that mold pretty easily.
I considered the Controller option, but, somehow, it doesn't fit my vision of OP. He is nowhere near as dedicated to his "companions" as the two obvious controllers - Soundwave and Blaster.
I think I'll handle it like this: his normal alt mode priority would be 2 (semi-trailer); in order to accommodate the trailer/battlestation, I will increase his alt mode priority to a 4. Roller will be his "special power" - a Link [Primary]. Even though links are supposed to be small, I think a medium Roller wouldn't be out of line, since it has no combat capabilities.
So, in the end, we have this:
Optimus Prime
Male Personality Autobot (ahem... Exile... yeah, right) Soldier 20
Gargantuan Transformer
Priorities: Alt Form Design 4, Form Feats 1, Ability Scores 5, Special Power 3, Gear 2
How does it look? Most of his ability points would go into Str and Con, then Wis and Cha (although I'd argue the Matrix grants him a huge Wisdom bonus of some sort).