There's at least 2 Engine Rooms on the ship - in The Naked Time Scotty calls out over the intercom: "Engineers, man your stations. Engine rooms, report. Cycling station, report. This will be an emergency restart of engines."
And I think it's reasonable to assume that there's one in each hull, or the crew would be really screwed if they ever had to separate the saucer!
I also don't think it's a stretch that they would be similar in appearance - they are both engineering control rooms after all and Starfleet does love its modular equipment! For example, those large wall consoles were seen in the Engine Room, Phaser Control and Auxiliary Control - why shouldn't other equipment have shared duties? The function of the large tube structure was never clearly defined, after all.
I don't think it's likely that the control rooms for warp engines and impulse engines would look alike. The very nature of the drive systems is extremely different, and impulse drives are rather simple in comparison. Presumably the impulse engine control room would be smaller and have different controls and readouts. Also, we know for a fact that the large structures in the middle of the engine room floor provide access to the dilithium crystals. It makes no sense that identical structures would be found in the impulse engineering room.
And let's look at the precedents of other starship designs. In ENT, the movies, TNG, VGR, etc., the impulse engines are always controlled from the same main engineering room as the warp engines. It stands to reason that if there are separate impulse control rooms, they're auxiliary facilities that don't get a lot of use. So there's no reason they'd be just as big as the main engine room.