NovaTac didn't make an 18650 body for the EDC line.
HDS made a few 18650 bodies for their EDC line (the predecessor of the NovaTacs), and they can be used with the NovaTacs as well. But, these 18650 bodies are very hard to come by.
HDS made a lot more 2xCR123A bodies, and they can be used with a 17670 cell on the NovaTac EDCs (do NOT use 2xCR123A cells). These bodies can also be easily modded to use 18650 cells - see this thread. Lighthound still has the HDS 2xCR123A body in stock.