I thought you could use "pipe" or "rolling" tobacco as a base. Of course, it would still need to be washed...
I've considered messing around with this as I found a place that has cooking flavors locally at a decent price. Just need to find a "safe" form of glycerin - the stuff I keep finding is the stuff you put up your darie-aire.
There are some posts about how other members made some.... (search: homemade shisha)