This sums up the last decade of my life. In my spare time I stare out the window trying to dream up a "rule system" that coughs up both relativity and quantum mechanics. It's very hard to even reproduce the basics, let alone the more irritating things like the three generations of particles. That in particular is a good "acid test", and it isn't even mentioned by 90% of the conceptual papers I've been skimming. Quantum gravity, loop this, string that... show me three generations and how those particles conspire to make gravity waves, and then I'll be interested.

Right now I'm toying around with a particularly mathematically elegant model with (IMHO) incredibly beautiful "symmetry" in the sense that the equations are both trivially simple yet capable of producing a rich particle zoo, but still limited to a small finite set. My problem is that I'd need a few petabytes of memory to play around with it sufficiently to see if it passes the basic tests.

I'm hoping Moore's law will allow me to run some simulations before I die of old age...