You could always switch to futures and avoid the pattern day trader rule completely. If you primarily trade the index ETFs (QQQQ, DIA, SPY), then you basically have the direct crossovers in the e-minis (NQ, YM, ES) and there's plenty of other action to go around as well (gold, oil, etc, etc). Some of the futures have good liquidity and can be traded around the clock (for example, the 6E/EC Euro future is pretty active during the London session as well as the US). As with any trading vehicle, there are plenty of potential "gotchyas", and you can get your ass handed to you on a platter quick if you're not careful (but I think that applies to anything), but it is one option.
If you're not a huge volume trader, you'll pay around $4-5 for a round trip per contract, but as was stated before, if you're a bigger fish, you can negotiate (ah, to dream).
I have a full-time day job (that I have no intention of giving up), and I'm studying the futures markets right now with the intention of eventually (after lots of practice) day-trading futures and also using options on ETFs as longer term trades in my IRA. The cool thing about IB is that they let you trade futures in an IRA. (I'm sure there are others, I'm just most familiar with IB)