Well, other than spell lists and monsters, my little m20 ruleset is complete, believe it or not. That's, of course, the beauty of m20--it's fully compatible with the SRD, yet almost outrageously simplified in comparison. The only thing left to do now is to playtest it a bit and see how it works.
I'm a little bit hesitant to playtest with my regular group, as they're veterans of d20 play, and will just be mentally filling in the gaps all the time rather than really playing m20 with the "lite" approach that it begs, but my kids, who keep asking me about my "D&D night" (we still say that for simplicity sake, even though we're playing Star Wars currently) and have had a few good experiences with my running things for them here and there, might be a good group to trial it with first. Their lack of experience will show how robustly it works, and point out where I've got holes that might need filling to get the experience I want, which is fast and loose, handwavey "rulings" favored play, but with a system that feels familiar enough to me, as a d20 veteran, that I don't have to wonder about rules questions, or how the game "should" be played, because it's either expressly not addressed and left in the GM's hands, or because it is specifically and clearly called out in the text of the m20 rules variant.
And while I enjoy the adult interactions and ability to focus on adult themes that is inherent in playing with guys my age, playing with my kids should be a rewarding enterprise in its own right too, as well as a good trial of what--if anything--my brusque restructuring of the m20 conceits need to be re-addressed. So, in the meantime, I'm ready to let the m20 tag go a little fallow until after I've had time to playtest a bit, after which point I'll give an update and conclusions.