You really only have a couple of options
1. Change the clutch bell...Might not help all that much, depending on how big you go. If you are running a 16, try a 18 or even a 20 tooth
2. Loosen the slipper. You might loose some of the initial low end, but you have to savricifce something to keep the front end down. I may be mistaken, but I think that this is what 2wd stadium truck have to do when they race so as to keep all 4 wheels down.
3. Softer springs and shock oil in the back. This will help the shocks compress easier, and help to keep the front end from flying up.
Your answer may be in a combination of these.