Most of the alternative bedding materials are so cost prohibitive for me to use as cat litter with scooping usage, let alone rodent litter where its generally all tossed weekly. Aspen is about as expensive as I'm willing to go.
However I have tried PaPurr, which is a pelletized recycled paper litter that works pretty good. It was on sale at Petsmart a couple of months back, $8 for a 40lb bag. This is the non-scoopable size, btw.
It worked pretty good for both cat and rodent applications at keeping the odor and wetness down. However it was slightly dusty, it was heavy, so it may not work in a rack application, I didn't like the fragrance of it (gave me a headache), and you had to end up putting nesting material in it anyway (timothy hay and shredded newspaper being my choices).
That being said, I'll just stick with the aspen shavings. =)
On a side note:
I REALLY liked the Aspen Supreme pellets, but again they are expensive as all hell and Petsmart WILL NOT special order it in larger bags for me. And buying 10 5lb bags for $7 each is assinine, imho.
I also really liked the Lifemate Hemp bedding, but again, it was even more expensive than the aspen pellets. Amazing how expensive some of the cheapest products to grow can be.