any old XMS3 DDR3 kits available?

I'm doing one last spruce up on my machine to keep it going for another year or two (can't afford a whole new system build) It's still running fine for my needs, well almost - Photoshop batch processing and multi-track sound editing both hit 100% on my RAM and CPU, and I now need to start learning how to do 3D Revit-Robot too which is greedy on the system resources. Have a 2nd hand i7-870 arriving from ebay and now trying to find a 4x4GB DDR3 1.5V kit that is actually listed in my motherboard's QVL list is proving nigh-on impossible. Do Corsair know of anywhere with some XMS3 kits left? I can find vengeance kits but google finds a number of disgruntled people who couldn't get it to boot with my motherboard so I'm a bit worried about buying those...

edit: or any guidance on how to check which vengeance low-profile would be compatible with 1156 - from what I can gather it's the newer memory densities that (probably) cause the issue even if the overall memory capacity is within the 4GB per stick limit.