Honestly what I would do is simply use the mechanics already provided and just reskin them. That's not a YT-1300, that's the Ebon Hawk. Give a Magnaguard a blaster rifle and you've got an HK droid. So on and so forth.
This is the approach I'm currently going with. Reskin with the RPG, reskin using X-Wing for the starfighter scale engagements, and reskin using Armada for the capital scale engagements.