I talked to Calvin Slobodian at the Calgary Comic & Toy Expo a couple of weeks back about pre-Robin Tecs. He said he has#28-#37 (plus a bunch after that) in FNish or a bit better (he said his copy of #31 is FN/VF) condition. They are in his personal collection, though, and I don't believe they are for sale.
He did have a great selection of GA books at the show, with a nice early Batman run starting at #4 I believe. There were also some Tecs in the 40s and 50s on the wall as well, and a few nice Timelys scattered around.