Pumps that won't add heat to my tank?

I'm running a 40 gallon reef tank with no sump, a protein skimmer, and
two Maxijet 900 pumps in the upper left/right back part of the tank
(hanging off the top rim of the tank). You can see the tank on the web
page:

http://www.benslade.com/reef.html

My question is, are there any sort of pumps that I can use to replace
the Maxijets where the heat generating part of the pump is out of the
water? But where I can still mount the pumps in the upper left/right
back of the tank? I'd like to also go with bigger pumps than the
maxijet 900's if possible.

Thanks
Ben Slade
Washington DC
PublicMailbox at benslade dot com
(append 030516 to the subject line to bypass spam filters)