Hmmm, thats the funny thing, you've covered most of the major players (clone wise), bout the only one you havent done is the "Rifleman" clone (the poor SOB who got decapitated along with Gree) but that would take some heavy modification on the base armor...the other option is the odd looking helmeted Troopers from Kenobi's force, engineers i think they were, not too sure.
Could be worth doing the "Generic" ARC trooper the customising it to be a character, tho seeing as Rex is basically in the ARC trooper armor it is really not much of a leap.
You could just let the creative juices flow and just create your own character, based around the clone armor etc, i know its dangerously close to being "EU" but meh, you've pretty much covered most of the clone incarnations.