Waterblock manufacturers have moved away from making water blocks for RAM... RAM is simply too efficient and low power to benefit in any way performance wise outside of competitive overclocking. Those tall toothy heat sinks that continued to be supplied on DDR3 had one cooling purpose and that was to "look cool".
Still many peeps do it just for aesthetics and the ever justifiable "cause I can", but because of the lack of performance benefit to 99.7% of users... these are less plentiful than they used to be. And the ones that are, are mostly "generic" or "universal".
Tho FCPU has been not been "open for business" of late, I still use the website to see what's available as it has the biggest selection, it's great for finding what is available and the site is very fast loading. Once I do that and find the product I want, then I go and look for who has it.
http://www.frozencpu.com/cat/l2/g30/c225/list/p1/Liquid_Cooling-Water_Blocks_RAM.html
http://www.performance-pcs.com/water-blocks-ram