I have tried a Torp Boat in a Rapier Class escort (T2) but have been underimpressed thus far. The general Idea is that one could run with minimum weapon power allocation but so far it's been a real pain to drop enemy shields in any reasonable time frame. (Even with maxed out Tachyon Beam and running High Aux and Deflector power mods.)
More testing is obviously needed and YMMV....
I was running 3 quantum's in the front and a Quantum Mine in the rear.
Haven't gona all torp, but in beta I rolled a Tier 2 Escort with 2 forward torps and a Beam Array. To punch shields faster than all torpedos. It worked pretty well, but I imagine all torps would be a bit underpowered. Beam weapons really help with shields.