I hear Applied Plastics does A.N.T.'s work.
www.appliedplastics.com
You might try contacting the guys at Indy Fab in Somerville (
http://www.ifbikes.com/) and see if your stuff could ride along with theirs or if they might otherwise be interested in helping you out (quoting you a price, telling you who else could do it)
(both of the above are powdercoats)
Or you could go DIY. Strip the frame (optional) with chemical stripper, sandpaper, or sandblasting. If sandblasting be sure to mask off the threads in the BB shell. If you don't strip the frame, be sure to at least sand off any surface rust. Apply a few coats of primer (optional, but highly recommended, esp if you didn't strip it). Paint with as many coats as you can stand to put on in your favorite colors of spray enamel. Remember, lots of thin layers. If you think you've put on enough coats, go for another 4 or 5. Then repeat with clear coat. A few cans of clear coat does wonders for durability. Viola.