I've suggested before a neutral set of races that act as mercenaries like this before, including trading, crafting, fighting on both sides, not being able to reap any open world/RvR benefits if that ever makes it in, etc.
there are already Ferengi AND Orion ships cruising around the Eti Eridanis sector.
try bartering with them of your Fed toon. fly up to them (gotta get close tho). enjoy the loots.
now try bartering with them on your Klingon. aren't the Orions suppose to be on our side? cuz...you cant.
not at Lt Cmdr, anyways-they tell you "there's nothing here for you-yet" (almost verbatim what they say)
so, question, anyone Commander-tier or above been able to trade w/these ships?
and btw, have you noticed on the Cryptic points store, Ferengis are an unlockable FEDERATION playable species?
so are Klingons...