this question might be better off in the ask the cuemaker section. last i saw, westinghouse micarta ferrules where going for 75-100 just for the ferrule/tip instilation, and then if you figure in the avg 150 of a shaft, i wish you luck. you might be best looking on the 2nd hand market, but then you run the risk of the replacement shaft not screwing on evenly and/or flush.
might give ryan, aka ratcues, a call over at muellers and see if he has any westinghouse micarta in stock. he does good work for a reasonable price.
the only two makers i can think of off hand with westinghouse stock are rhunde and az user mr hoppe.
You could also try out the new micarta from masonh. its gotten some good reviews and has been stated to be the closest to the old stuff yet.
Good luck with your search.