Abus chain loop sounds good in theory, but the size that would fit U-lock is 12KS. I have Abus 10KS and that sucker is pretty big, 12KS is a step up. That is one monstrous chain, it is prohibitively heavy even in shortest lengths. But the idea is sound, just need to use scaled down version of the chain or U-lock. That Kryptonite cinch ring chain with a smaller U-lock will probably fit the bill, need to try.