The Abyss is the same size (2x120mm fans) but twice as thick. costs £65 available in the UK from
OverclockedPC.co.uk (OCPC) . it's big enough that you'd need minimal airflow going over it for respectable cooling. I got the little Sister 'The Deep' on the way cause I could'nt fit an Abyss incase without major restructuring
(WTX ideal!), same with the car HC I have now...
PS, water flowing slower through the rad really does'nt work like you(and Me!)'d think it does. check out
BillA's (AKA unregistered) article for the truth, notice performance increase on graphs as flow is increased...