I'd be curious to know if Lee is still selling the couplers. I haven't been in contact with him for more than a year.
I'm still very happy with the FT coupler and the etched boxes, and I would recommend them to anyone who doesn't mind a "boutique" solution. But with body-mount couplers becoming more of an industry standard in N scale, this combination becomes less attractive since you either have to cut away the factory draft gear, or live with some kind of hybrid solution that involves retro-fitting the coupler to an oversize box. Neither approach is very appealing to me.

Eventually I'm going to take a look at the Arnold and BLI couplers, and I'll keep hoping for Proto-Mates to appear.