has a HUGE inventory of watercooling components, and they are also located in Canada.
is another alternative.
As for GPU cooling, almost any pump will handle the flow just fine, it's the radiator that will be the bottleneck of your loop.
Having said that, the radiator that comes with the DD 4101 is a Black Ice Xtreme, which being optimized for high-airflow fans, isn't that great for quietness.
http://www.ncix.com/products/index.php? ... e=Swiftech
The radiator will not fit inside the case without hacking it a bit, but the "Radbox" that ships with it will allow you to mount the radiator on the back of the case.
The radiator also has enough thermal capacity to cool your 8800GTS too, should you decide to incorporate it into the loop later on.
EDIT: Actually, this kit
offers much more for the price.
They're in the U.S. and you'll have to e-mail them about the order since it's an international order, but they've gained a damn good reputation for great customer service.