I know this gal who is an exceptional cook. She claims one of the best tomatoes to sun dry is 'Principe Borghese'.
Found it here-
Found some interesting comments about a drying process for this tomato here-
I use sun dried tomatoes in a few recipes. I've always bought them before but might like to try sun drying them if the process is not too complicated. Anyone out there sun dried any tomatoes before and if so how did you do it? There's supposed to be a way to do it where you don't need to buy a dehydrator.