There are several 1/2A designs prior to December 1970 that were published as 1/2A stunt ships.  Not many of these could be considered "serious" stunt designs in the sense similar to the capabilities of more "recent" designs like the Mathis Pinto or the Baron BareCat.  However, there are several that would make into a reasonably capable stunt ship.  Examples from the list below include the Envoy and the Spacebound.

There are others that would prove interesting using a highly offset engine or engines capable of using long to very long lines.  Examples below are the Charger and the Space-Liner (a twin).

Then, there are the small (.010 and .020 power) ultra lights that will do at least parts of the pattern on very short lines but the pilot might have to turn very fast on level flight.  (Those were interesting times.)

Here is what I have in my collection of 1/2A articles:

Blue Tail Fly by Vern Clements.  October 1956 Model Airplane News.  21" span, 105 sq in, for Thermal Hopper or Atwood/Wasp.

Cheshire Kitten by W.A. Pollard.  June 1958 Aeromodeller.  21" span

Charger by Jim Mayfield.  October 1970 American Aircraft Modeler.  30" span, about 180 sq in.  Interesting design - swept back wing with engine mounted in the LE of the wing near the center section with about 30^o offset.  For a TD.  (Published on Oct, 70 but a case might be presented that the thing was actually designed prior to the Dec, 60 cutoff date for the PAMPA classic stunt rules.)

Draggin' by Jerry Peck.  August 1956 Model Airplane News.  22" span, about 140 sq in.  Flying wing.

Elf Cat by J.H. Bailey.  January 1959 Aeromodeller.  33" span, about 190 sq in.  Full fuselage.  Flaps.

Envoy by Edwin Hunt.  August 1964 Model Airplane News.  Attractive airplane.  Looks like a scaled  down full size stunter.  Dimensions uncertain but somewhere between 28"  and 30" span.  about 170 sq in.  Inverted cowled engine.

Firestrike by O. C. Povey.  December 1968 Aeromodeller.  delta wing.  13" span, 150 sq in.

Half-A Twin by Harold deBolt.  December 1951 Air Trails.  Twin Wasps.  26" span, about 150 sq in.  Profile fuselage.

Hopper by Ray Booth.  March 1959 Flying Models.    35" span about 220 sq in.  Plans show a Cub .099 but a Cox TD or Norvel would pull this just fine.  Good airfoil.  Could be built very light.

Jersey Bounce by Larry Scarinzi.  October 1958 Flying models.  22" span, 110 sq in.  Really a combat ship with a profile fuselage, lots of engine offset.

Liberty Bell by Charles Mackey.  September 1967 American Modeler.  A sheet wood flying pancake, will do a pattern with a Cox .010 on 15 to 20 foot lines.  (You need to understand that Charles could think outside of the box.)

Lil stingray by Harold Price.  Small twin boom  for Cox .020.  Weighs 1 oz.  Flies pattern on 20' lines.

Mighty Mouse by M. Kelly.  May 1953 Model Aircraft.  (From UK)  16" span, built up wing.  maybe 80 sq in.  Has flaps! Full fuselage  "Will do all the tricks on 30 ft lines."

Queen Bee by Larry Scarinzi.  June 1960 Model airplane news.  Bipe.  11" span, 65 sq in.  For the Cox .020 Babe Bee.  will do vertical eights on 15 foot lines.

Sharpoon by Keith Laumer.  November 1961 Aeromodeller.  36" span, 200 sq in.  Straight wing, no flaps. box fuselage, trike gear.

Spacebound by M. Constant.  August 1966 Aeromodeller.  33.5" span, about 200 sq in.  A "reduced" size Sirotkin Spacehound.  Full flaps, inverted cowled engine.

Spook by Wellington Way.  May 1959 Flying Models.  20" span, 90 sq in.

Strato-Liner by Carl Rosteen.  February 1957 Model airplane News.  about 25" span, about 140 sq in.Full fuselage wing and tail convfiguration.  Twin engine with one engine in nose, the second engine on outboard wing tip conted out 65^o.  Shows two .049 McCoy Diesels.  Does a pattern on 200 ft lines!

Sweetheap by Ray Malmstrom.  September 1968 Aeromodeller.  22" span, 120 sq in.  Built up wing.  Profile fuselage.

Teenie Genie by Roy L. Clough, Jr.  October, 1955 Air Trails Hobbies for Young Men.  16" span.  80 sq in.  Built up wing.  Box fuselage.  Simple, light and will do the pattern.

Vedette by W.I. Barret.  July 1968 Aeromodeller.  30" span, aobut 180 sq in.  Full fuselage, flaps, trike gear.   Vee tail.

Wee One by Bernie Shulman  May-June 1967 Flying Models.  15" span, about 55 sq in.   Flaps!  built up fuselage.  for Cox .010 or .020.  15 foot lines.

Keith

Does anyone have plans or info on the Baron Bare Cat? I don't think it was published, but knowing Bob B and Bill N, something is probably out there.

My list was from my collection of 1/2A designs that were published in the magazines and what would be Classic legal.  To my knowledge, plans for the Firebaby and the Baby Barnstormer were never published in the magazines.

Keith