$135? Really? I don't think that is pricey. Considering how much you probably spent on your PCE console, or how much brand new games for modern systems cost. $135 for a NES flash cart that will play pretty much every licensed NES game is a good deal.
Anyway, KRIKzz was asked about doing a NES EverDrive and he was not terribly interested in it last time it came up. Afterall he's done, Megadrive twice, N64, SNES, now makes the SD2SNES carts too, Master System, Game Gear, and now TG16/PCE. Compared to other systems the NES is pretty involved to make a flash cart for because of all the different memory mappers. The Gameboy/Gameboy Color has a few different mappers and is requested alot too. It may become a reality. Not so sure about NES. Also bear in mind he lives in a country where the NES doesn't exist. I think just Famicom clones maybe.