"Stiffer shocks I don't think would do anything because they can't stop lean, they just slow it down. This could be beneficial for a lean caused from bounce, but a slow steady state tip needs a stiffer spring to help control it."
I suppose thats true. I've read recently that a lot of the suspension tuners for KOH and other offroad racing series have been asking for MUCH lighter spring rates compared to the past, and can often dial out the downsides with shock tuning. That said, they also say the springs need to be just heavy enough to suspend the vehicle and carry the loads it needs to. I do know that bunch of guys in Colorado have started going with the "light spring" method with their buggies and harder core offroaders it seems like its paying off in both slow and fast speed applications. It is certainly a fine line to tread sometimes though.
One way to get a bit of the best of both worlds is to look at progressive springs that start out softer and get stiffer as they compress. Also, as you get stiffer springs, you'll have to worry about getting into coil bind (where the spring compresses fully and you get a hard stop) so it could possibly limit your suspension travel too. I'm not saying this is happening, just that its stuff to think about. Torsion bar style sway bars like the Curry Anti-Rock ones are worth looking at since they are designed for long travel applications and have varying length arms so you have more options on where to put them.