As title says. What I've come up with is MC80AC+Ackbar+Defiance+ConcentrateFireDial+EnchancedArmament+OpeningSalvo for 11 red dice.
Most dice of a single color?
ISD-2 with Devastator (no defense tokens and has not attacked yet), Concentrate Fire dial, Opening Salvo, QBT, for 12 blue dice.
Executor II will also be able to get to 11 red dice (technically the quad turbolaser die is not rolled, and you would need an accuracy in the original roll):
Executor II - 5 red
Opening Salvo - +2 red
Spinals - +1 red
Concentrate fire dial& token + Ravager - +2 red
Quad turbolaser cannons - +1 red
...and an ISD II can get 12 blues:
ISD II - 4 blue
Devastator - +4 blue
Concentrate fire - +1 blue
Opening Salvo - +2 blue
QBT - +1 blue
Max I get for blacks is 10: Forgot Sato! itzSteve has it below.
MC75 ordnance front - 3 black
Opening salvo - +2 black
Concentrate fire - +1 black
External racks - +2 black
Expanded launchers - +2 black
Edited by jp82729
A Sato MC75 Ordnance Cruiser front arc with Expanded Launchers, External Racks, Con fire, opening salvo. 12 black dice!