Hi Dean,
glad to hear you are interested in classic pattern and a biplane lover. I've been flying pattern since the early '70s when I was a young teenager. One of my earliest competitive airplanes was an Aeromaster which I have very fond memories of. I grew up in Massachussetts and was fortunate to meet Lou Andrews. He introduced himself to me after one of my flights at a contest and was very encouraging - a really nice guy!
Biplanes are a bit more work simply because of the 'extra' wing which adds some trimming complexities, but once you are happy with the airplane it is just a matter of practice, practice, practice. As for potential airplanes, the Aeromaster is a personal favorite and the Skybolt flies pretty well, too. One of the best biplanes from that era was the Pulsar, but it is long out of production. You might find a kit on eBay or at the Wrams show. Hopefully, it might be kitted again. Another design from the '70s is the Sunray which was published in R/C Modeler magazine (I don't know if they still distribute their plans). I built one and loved it - a great flying airplane. You mentioned the Stampe, Jungmeister and I'll add the Pitts and Great Lakes which are terrific looking bipes that fly well, though may not be perfectly suited to classic pattern aerobatics. Two more bipes, not to be overlooked, competed at the '89 F3A world championships; the Shamrock of Tobias Schulz and The Fyg Leaf of Tony Frackowiak. The Shamrock was kitted, though very hard to find at present. I would love to get a copy of the Fyg Leaf plans, myself, a great flying airplane that Tony flew with a YS 61 long stroke, but I would probably go with a YS 115 4-stroke. The final two bipes that I will note are the Goldberg Ultimate and the Marutaka Reed Falcon. The Ultimate is a great flying bipe and an easy build and kits appear regularly on ebay (I think there is one there now). The Reed Falcon is a very nice Japanese kit which is harder to find, but there was one on ebay about 2 months ago which never sold. Of course there are many ARFs available in various sizes, too. If you want the latest in F3A biplane design (in a kit) there is one available here in the US from InsightRC called the Harmony II as well as a Japanese kit, called the Accuracy, from Naruke Hobbies.
Good luck!
-Will