can anyone tell me of a frame I could use under my shoebox? Or has anyone had any experience in using another type of frame?

Well you could use a custom made frame by one of the aftermarket companies OR you could use an S10 pickup frame. Be prepared for alot of fabrication with most frame swaps. you will need to make everything from body mounts, radiator mounts, & motor mounts just to name a few. The best advice I can give is measure out everything and decide which will be close. I'm putting an S10 frame under my 41 ford and I've put a Ranger frame under a 48 ford pick up. They are alot of work and most people say don't do it for any number of reasons. I can tell you this, for my money this is the best option. Like I said measure, measure, measure and do some searches on the net.

Well,since I have more time and ambition than money;I'll start measuring.

If you decide on an S10 frame shoot for a standard cab/extended bed (approx 117.9 inches) or a extended cab (121 inches). These two body styles provide the best platforms for shortening & lengthing depending on your needs. The S10 frames have a factory weld seam that can be ground down. Once this weld is ground the two halves slide together so you can lengthen or shorten from that point.
other tips:
-Look for an S10 extreme truck it is already lowered a few inches from the factory and has a quick ratio steering box.
-4.3L V6 trucks are said to have better sway bars but stiffer springs.
-4x4 truck rearends are stronger and longer if I remember right.
-Get the steering column, brake booster, master cyl. ,and brake pedal assembly if you desire.
-1st generation mustang gas tanks fit nicely where the spare tire would sit on the S10s.