Filco is a legendary manufacturer of mechanical keyboards, which for some reason stopped making them. So, finding Filcos for sale (especially new ones) is an opportunity indeed. Looks like a UK-based outfit called The Keyboard Company has a stash of various models that they are selling via Amazon. I’ll list the models available here, but note that availability on all of these is pretty limited so there’s no guarantee they will be in stock.
(Reminder – here’s my earlier Cherry MX primer on the differences between each type of switch in terms of linear vs tactile response)
Here’s the manufacturer page – Filco Majestouch keyboards on Amazon.com
And here’s the current stock. All of these support full N-key rollover. Prices range from $140 to $180.
Full-size 104 keys: