Wireless mouse recommendations?

Hello
I am wondering if there is any wireless mouse capable of working from one side of a room to the other. It would need to function while passing over a desk and covering a distance of roughly 15 to 20 feet.

Little things like this end up costing you way more than you think: http://www.wireless-computing.com/products/laser-mouse/

I know they aren't cheap... I guess I'm wondering what kind of specs a mouse like that actually needs? What makes it necessary to have that kind of range?

Look, I’ve got a much stronger receiver than those average Joe types who usually have to hover within two or three feet of their setup. If you're looking to save a few bucks, there are plenty of budget-friendly combos out there like this one: http://www.iogear.com/product/GKM552R/