If you are going to get it CNC'd from Aluminum, why bother with the extra step of going from plug to mold. Go direct to mold. I think you could get something for like a 2m pattern fuse for less than 10k, but it will definitely be in mid to high four figures. I design, and have had built, female vacuum form molds from aluminum, and we pull thousands of parts from them, so the cost gets spread out.

If you think you will sell a thousand, that's $10/unit for a $10k mold. I fly pattern, and would be hesitant to invest that much. A successful design may sell one to two thousand units over it's market life, but most sell less than that. The materials and labor to carve a plug and pull a resin mold can be less than $1k, if the builder is a pro. A beginner risk loosing his arse if there are snags (been there, done that)