I've had 2 bubble font Russians, a General Guitar Gadgets clone, EHX Bass Big Muff, W&C Tall Font Russian and the ARC Big Green Pi. Out of the clones, the W&C sounds most like an original green. Saying that, I've never heard anything that sounds quite like an original. Whether that is just me being picky, I can't say. The originals have a boxiness and growl that I've not seen replicated.
I'm tempted to try a W&C Box of War. There's a comparison on Youtube that sounds spot-on...
[url="http://www.youtube.com/watch?v=t1-ixHywxdg"]http://www.youtube.com/watch?v=t1-ixHywxdg[/url]