10" is not much for any kind of connection. You might be able to use a 3" nipple, and a 6" one with a "Dresser" compression coupling, if you can find a short one. Slide the Dresser on to the 6" nipple with only one gland on it. Put the removed gland on to the 3" nipple. Tighten the 6" nipple into the fitting. Slide the Dresser all the way back. Screw in the 3" nipple with the gland on it, the slide that gland back against its fitting. Slide the Dresser and its gland onto the 3" nipple. Insert the bolts and tighten the nuts. You might be able to do the same thing with a PVC "FloCoupling" but sometimes getting the "locknuts" straight and tight is difficult.