Is it possible to blend the two sets of diodes together instead of have a switch to choose between them? I'm thinking that the pot all the way one direction would be the symmetrical clipping, and all the way the other direction would be the asymmetrical clipping, but in the middle it would be half of each.
Yep
http://www.muzique.com/lab/warp.htm
Is this what people refer to as a warp control?
According the AMZ it is! I imagine a lot of people got their part of their start from AMZ's teat, so probably. I think warp would be an overarching term, in this case, referring to any kind of harmonic mixing. The OP's idea is just one way to achieve it.
So it looks like this answers my question:
(http://www.muzique.com/images/warp9.gif)
...and might be a little over my head too. :-\
Pretty neat, I have a Green Bean I have yet to build and was thinking of the on-off-on approach for clipping, but this sounds equally as interesting.