As long as the frame is small enough, longer barrels needn't be bothersome in concealed carry. I sometimes CC a Ruger Police Service Six, with a 4" barrel, and find it less of a chore than a 2.5" S&W M66 I was stuck with on a few occasions. The problem of drawing the piece from a holster is where the barrel length can work against you. The muzzle MUST clear the holster, or bad things happen. Rear-canting the muzzle slightly can help, though it makes getting a solid gun-to-hand grip more difficult.
I can't draw a 2.5" barreled revolver better, faster or cleaner than I can with a 4" barreled revolver. But for some reason, I CAN shoot discernibly lower scores with the 2.5" revolver. The longer barrels mean greater weight, but it would be up to the wearer to decide whether the difference is enough to be inconvenient.
The only 5" barreled revolver I've tried to draw from concealment was a S&W M27, which is the same frame on which their .44 Magnum is built. I DID seem to be slower, and shoot lower scores with it than with my PS-6, or a friend's 4" S&W M19, but I honestly can't say with certainty whether it was the 1" longer barrel, or the larger frame. If I had to guess, I'd attribute it to the frame size.
A 5" 9mm revolver would probably get all the ballistic potential the cartridge has to offer. A 5" .357 would probably work better. If it proves cumbersome to conceal/draw, gunsmithing can fix that.