Dr. Leland R. Dexter has announced that he, through Micro Nitro Rocketry, will be producing "Caldera-style" Micro and Mini Hybrids. Rene Caldera designed and sold parts kits for the original Micro-Hybrid design. These motors used commercial, 8g food-grade nitrous chargers as an oxidizer and wound paper grains as a fuel (you could use other materials, for instance I made potassium nitrate/epoxy grains). Leland has secured the rights to reproduce Rene's Micro design and will be producing a Mini sized motor, which will use the larger 16g charger.
He has detailed documentation on his motors and reports that he has done extensive testing. As of post time, he also has one rocket kit available, the Whippet. Note these rockets will require an altimeter or other device to detect apogee and eject the 'chute.
Here is one of several videos from his site, showing a modified Quest Bright Hawk flying to 1,395 feet on an E-class mini-hybrid (16 gram charger and a grain cast from HTPB and powdered aluminum).