Just discovered this really promising looking plugin - currently in Beta but available as open-source so you can grab it from their website (use the link to nightly builds).
Basically a Gig Performer for overdrives! You can insert various blocks and link them all together however you wish to design your own overdrives/distortions. Loads of really cool blocks in there to do all sorts of things - fancy a chorus between your clipping and tone stage? Sure! Want to run a Big Muff through a toy speaker IR? Go for it!
Good little video here showing some of the main drive blocks - but well worth a download and play around with.
