That piece of sheet metal in front of the graphics card is just stupid, maybe time to remove it?
I think the Arctic Cooling Accelero Twin Turbo (non Pro version - Important!) may fit, since it got a four heatpipe design it gives pretty good cooling capacity, better than the L2 for sure.
It's pretty much a S1 with lower height and fans included.http://www.xbitlabs.com/misc/picture/?s ... nb.jpg&1=1
But you have to find out if it fits, I don't know, but I think it's possible with some modding/hammer.
It's not being produced anymore, but can still be bought in stores: http://www.arctic.ac/en/p/cooling/eol/v ... turbo.html
Another alternative is the Scythe Musashi, the pipes goes in the other direction, meaning that it's easy to lower the height just by cutting the fins and swap the 100 mm fans with 92 mm.
I bet this one requires making hole in front of the card, otherwise it won't fit.