I made this offer a few months ago:
I've read a lot of posts recently written by TS owners curious about slide lightening and it gave me an idea: since I converted my TS into a 9mm Open gun, my lightened .40 slide mostly just sits in my safe, if anyone is interested in some sort of rental or purchase with a trade in or trial period, please send me a PM.
There seems to be some interest in buying this, but unfortunately, there is is no established market for TS conversions, so I'll share my thought process:
The mags complete with CZC bases, springs and followers (21 rounds) cost $100 each, I paid Rich at Canyon Creek Custom $125 for the slide cuts and when I discussed the possibility of getting a Czechmate with .40 top end they quoted $500 for the top end; Tanfoglio Limited conversions run $485.
I think $900 shipped would be fair for the top end with four 140mm mags or $750 with four stock 17 round mags, but I'll certainly listen to any offer. As I understand this is a pretty unique item I'm also offering a "money back guarantee", so if you're not satisfied for any reason, you could send the parts back for a refund (minus $20 insured shipping).