I'm going to have to admit that the 700p is probably one of the more durable PDA phones you can get. Most newer models are 90% screen and a lot more fragile, and with the 700p you have a pretty solid casing and a recessed screen (you'll probably notice that most newer touch screen PDA phones do not). Also, Palm OS is dead so you wont be finding any new devices running it, unfortunately. You may want to look at the Centro (on Verizon) for a cheap alternative, but its mostly the same as the 700p but with a smaller screen.

If you're really worried about durability, I would suggest a Blackberry (any model but the Storm). These are non touch screen PDAs that are rock solid (I used to kick mine across parking lots). Text messaging will be easy but document editing will be a little tougher, although possible.

Hope this helps...