While some of the alternative options are certainly not
permie friendly, there are a few that will work well. There is a metal casting forum that has a list of homemade refractory compounds that can give some ideas:
Alloy Avenue DIY Refractory Compositions
It took me quite a while to hunt it down, but it turned out there was a pottery supply store in a small hole on the rear side of a strip mall where you would never find it on your own. The lady running the place was very nice, and although confused with what I was doing (making an aluminum melting furnace) she was very helpful. I picked up a 40 pound bag of fire clay, 10 pounds each of bentonite clay and alumina, all for something like $50 several years ago. You can find cheaper online, but then the shipping makes it much more expensive. It may take a lot of digging through numerous sources (masonry supply, pottery supply, heating oil furnace supply) to find a place close enough to be worthwhile to drive there. I know of one place online that sells smaller quantities of refractory cement for reasonable prices with shipping here:
High Temperature Tools and Refractory
I haven't used them but came across them in the Alloy Avenue forums from the first link. There are lots of people doing casting or knife making that use castable refractory, so it would be a good idea to seek these people out locally if your other efforts fail. The people at those forums are a friendly bunch and there might be someone with more local information to point you in the right direction.
There is a lot of info on those forums about hot faces, insulation, flux, and other things that can be directly applied to both a furnace and a rocket stove/mass heater. I would strongly encourage anyone interested in using homemade refractories or making multiple rockets to go there to learn of other people's successes and failures to save yourself a lot of money and grief. For a one-off rocket you are much better off using a commercial product and following the instructions as closely as is reasonable in order to have the best chance of success.