At some point when I actually have a test 4.0 install running with our real dataset, I'm willing to help test as well. Then again, if it works with 1000 posts it's going to work with 60 million, so I'm not really that useful
I would really love an updated version that runs on 3.6 that takes advantage of all the Sphinx goodies, since I don't see us moving to 4.0 for close to a year. All of the custom code we've written has to be ported and tested, and being the lone admin on a site this big has my hands full a lot of the time.