well in the past i built a gingery machine and used it with some success but not for parts to sell.
I recently purchased an emco 2/3 oz pnuematic injection molder, which is a bench top unit. I do have a CNC X3 mill as well as a couple lathes. So I would assume you would need at least a mill, cnc will make it easier unless you machining skills, then some type of bench top machine. Iasco-tesco.com sells them as one source where you can get into them for $1500 as well as injectionmolder.com too
Then I would assume you would need at least an X2 mill, Cnc'd to make your parts. So that means you also need a cad/cam software to draw and machine your parts (run the mill).
As far as reverse engineering I am not sure what you are trying to reverse so that is hard to comment. I would say rubber molding and liquid plastic but you have experience with that already. with these small bench top injection machines you could make a mold out of aluminum epoxy and run anywhere from 100-1000 parts per mold before they break down I am sure.