I used to have a 3.5" 27 and now have a 3.5" 29. I gave up trying to have holsters made that fit "perfectly" after several tries. It seems none of the custom makers I talked to (and I contacted quite a few) has an actual 27 to mold a holster from and so they guesstimate it using a generic 4" N-frame dummy and cut the leather shorter. I was surprised that even old timers like Sparks and Alessi didn't have a 3.5" model to work with.
I've bought holsters from Milt Sparks, Fist, and 5 Shot and they all ended up being too long, sometimes just a tiny bit and sometimes quite a bit. All of them worked fine of course, it's just the principle of it that drives me nuts. I love to see a well made holster with the leather boned over the muzzle to protect it, and they can't do that when they're using the wrong gun. Plus I'm sure the shorter 27 cylinder and corresponding shorter OAL adds to the trouble. The only good thing about it is that when I got the model 29, which is a bit longer due to the longer cylinder, the holsters still worked okay.
I sold some of the holsters and currently only use the 5 Shot SAP (Snap Attachment Pancake) holsters for OWB, and Mark Garrity and Mitch Rosen IWB's which were actually made for 4" guns. I don't mind the longer leather for IWB because I feel it makes the holsters more comfortable and stable.
Here's some pics of my holsters. I highly recommend John Ralston at 5 Shot Leather, he does outstanding work and is very accomodating.
5 Shot SAP with elephant:
5 Shot SAP with crocodile:
Mark Garrity Incognito Deluxe
Mitch Rosen ARG