Well Brian, I have to admit it has crossed my mind. I've even investigated the possibility of casting them in metal using a local facility. They were very helpful, but the cost was going to be high. So, there are two main issues I face: one, I'm not there yet in terms of sculpting ability. I make lots of mistakes which I have to stop and correct. I find some of them during the painting process! Why I don't notice them beforehand is still a mystery to me... Some of the mistakes can be corrected via painting, while others require surgery and more puttywork. Under no circumstances would I ask a customer to fix my shape, proportion, perspective, or other sculpting errors. Wolfgang's comment about the small hands and fingers is a case in point. They do look small - until I explain why; the forearm is angled slightly away from the body, then the hand is bent back to the chest/shoulder. If I have to explain it, then I feel something's wrong - or not as good as it should be.
For the most part, I can render a variety of textures from cloth, to suede, to fur and I'm OK with clothing wrinkles, drapery, chain mail, and plate armor. My basic anatomy from the neck down is OK, but I still have those issues that I mentioned above. My depiction of hair can run hot or cold, but it's usually lukewarm... Faces are still an issue. I really want to properly render a face, but I've resorted to shallow depressions for eye sockets, slight bumps for noses and cheekbones, and engraved eyes and lips. Basically, I'm emulating Yvan Durand's technique on one of his Gil Elvgren based pinups (the one I used for my 'Santa's Helper' conversion).
The second issue has to do with my ability to commit to something I enjoy as a hobby, but may find that as job may get old fast. I used to be a very prolific aircraft and armor builder, then I got a post-military career job in the hobby industry and it very quickly killed my interest. After a 60+ hour week eyeball deep in kits, books, magazine, accessories and supplies, the last thing in the world I wanted to do when I came home was build a model. I'm very much afraid the same thing could happen if I started cranking out resin flats.
Still tempting, tho'.
Cheers,
Glen