I think you have an eye for nice bikes. That Suburban was a quality bike. Draw back is the weight will slow it down a bit. Seat may still be to small too. If you really like it though try www.schwinnbike.com . Under Community in the Forums section there is a classifieds. Post a want add and I bet someone can help out. Schwinn also made the Breeze, Collegiate, and possibly a few others in that style. Though most where single/coaster brake and 3 speeds.

Can you raise the Handlebar stem on your current bike? This will push your weight back more without sacrificing seat height. I was real nervous when I first started ridding with my seat higher too, but am very used to it now.