Well, I came up with my solution 10 years ago. Just go to a big name fabric store (Rossy in Montreal is perfect). You'll find rope in the exact same quality & thickness Lego is using, for very cheap.
But it probably won't be black (My store only had light tan at the time). So I went to buy some black dye. They sell those in small black boxes and are very cheap. Pour the contents in hot water, simmer the rope for a few hours. Voila, a lifetime of black Lego rope!
And I am still not even close of using up my original batch made in 2002 that I tainted myself. And it's still black as ever.
So for those looking for those ultra long ropes from set 8288 - crawler crane, don't pay those ridiculous prices on bricklink - the ropes you taint yourself end up identical!
Edited by SheepEater, 02 July 2012 - 09:06 PM.