Have you considered doing spot type variant retextures on the ships you've already done? Also, I must say I like the disruptor ports on the Lyran FF - have you thought about using that for the rest of the ships (it seems the DD will have them as well)?
Also, there's a pic of an unpainted model in the starfleet games store on ADB's website of the bottom of the STT, which shows the battery banks and the maulers. Might be good as a base if you want to go that way.