Staying with the Pronto NG line the TSU7000 or TSU7500 would allow for using the same configuration file without skipping a beat. The TSU7x00 remotes are identical to your TSU3500, but offering a color display and greater memory capacity. You could also step up to the Pronto Professional line. The TSU9400 offers the same screen resolution, so you wouldn't need to rework any of your graphics out the gate per taking advantage of the full screen area. Only PNG transparencies are supported however. As such, any graphics contained in your configuration file using the "pixel in the upper most left corner" transparency option would need to be updated accordingly. The TSU9600 is certainly not out of the question as well though you'd want to rework all of your graphics to take advantage of the 640x480 screen area. Of course both the Pronto NG and Pronto Professional lines are discontinued. It's not very difficult to find used Pronto remotes and extenders on EBay in like-new condition however.