As far as an upgraded halogen, there's really nothing else that fits unfortunately.
the PSX24W bulb is a weird one... not too common.
What I did was order the LED upgrade from Diode Dynamics, the XML2 in 5000K Pure White.
They sound expensive, but are totally worth it if you value night time visibility while utilizing the factory light housings.
I think I paid about $130 for my set... I think it was money well spent. My safety is worth the cost. Plus they came with a 3 year warranty so I don't have to worry.