I don't want to disillusion anyone, but I consider the Prometheus (and the Intrepid it's derived from) a very unattractive design. Not so say I won't ever make one, but it isn't exactly at the top of my list. I tend to lean towards non canon or semi-canon ships as I get too caught up in making the canon versions accurate and nitpicking the most insignificant detail until I lose interest.
The Relentless is a variant on the Lakota type, and is the only Excelsior I've done recently. The Lakota has bigger impulse housings, different hull and engines, and no phaser strips. It's basically the Enterprise B with a new registry and red/orange impulse domes.