Your present equipment will do just fine in a Cub. There are several ARFs available, check the big mail order dealers in the magazines or on the web. Look for one about the same size as your trainer. Don't go too small because, as tail draggers go, Cubs are fairly tricky. They are short coupled and can turn and dart around on take off. They also will try to take off into the wind, no matter which way you want them to go.

Also, there are full wing Cubs and clipped wing Cubs. The clipped wing ones are modeled after full scale planes that had the wings cut down for better aerobatics. They tend to be more aerobatic as models, too. For the same wing span, the cilpped wing version would have a larger fuselage.

If you can afford it, you might consider a second radio. This way, you can warm up on your trainer and then fly the scale Cub. you can then leap frog the radios into newer planes, having one to fly while installing the other into a new plane.