1. From what I can tell, the Homedics TheraP magnetic wrist wrap, which was the popular brand that you're probably referring to, has been discontinued. Here's another brand that avocet8--who I consider one of the most knowledgeable experts in wraps--recommended as a replacement:
BD Injury and Treatment Prevention - Product Information
2. You use the clamp to hold down the mousepad. You could also use tape if you wanted.
3. I'm sure you could, but I'm not a big fan of hose clamps. Are you using hose clamps? How are they working for you?