I have found another 1911 already built for comp. with a Colt slide and barrel, but it has a stainless frame. The frame is made in Pomona, Ca. but I couldn't find a name on it. Can anyone enlighten me as to what company may have made the frame?
That would be my guess, too. JPE was largely an importer (they went out of business), and I believe that they imported 1911 frames, most likely from the Phillipines. It is no telling who actually manufactured them. It was possibly Armscor, but I say that because that is the only 1911 manufacturer from the Phillipines of which I am currently aware. It is also possible that the frame was imported in a less than 80% finished state and finished in California.
JPE supplied the frames for Brolin Arms, and the early Brolin frames had JPE as the prefix of their serial numbers. Does you frame's serial number have JPE in it? After Brolin went out of business, JPE sold the frames and some of them had the name JPE without the prefix in the serial numbers. After JPE went out of business, Sarco sold the frames in several different configurations, including some with Sarco on them.
From what I have heard of them, they are decent frames (like Armscor). Not necessarily "best of the best", but serviceable quality with servicable tolerances.