Id actually throw out a vote for the Prince Graphite Comp Series 110 (and also its 90sq version). Smaller headsize to the POG OS (its actually a 100sq), more flex and just a more comfortable racquet all round. Circa 1984 and most likely the fore-runner to the Diablo midplus although it plays like a slightly more flexible POG Longbody. Also throw in a vote for the Prince Graphite Pro. Nice flex and very versatile racquet.
Unless, of course, you only mean those Prince frames with the cross-bar.