Been seriously eyeing off one of these:
http://www.flojet.com/prodInfo/overv...000-124_ds.pdf
The 4405-501 model pump.
3.3GPM positive displacement pump (up to 40PSI or ~27m pressure head)
43W power draw
12VDC continuously rated motor
Just US$115 from
www.depcopump.com. For us Aussies, that's amazingly cheap. Cheaper than an Eheim 1250 sells for here in the big brown land.