Pizza box cardboard makes excellent filters. And yes, the back roll is awesome.

Video of a back roll:
YouTube - Daily Smoker - roll a joint - Inside Out

Yes, cigarette filters can be used for joints. Some people might complain about "excessive loss" of THC, but it's all preferences. Headshops and smokeshops should sell bags of cig filters, ready to be rolled. You can also order cigarette blanks online and then put whatever you want into a legit cig. :jointsmile: