Comment Re:Broader question.... (Score 1) 146
Go deep, not wide. Offer Fn layers and dedicated keys, but put those dedicated keys in back, not off to the side. If you do expand to the side, expand left, not right.
You may want a Tipro MID, though those are hard to come by in the U.S.
Cherry MX Black switches (heavy linear), relegendable keys on the top three rows. You can get them in either a matrix layout or a staggered ANSI or ISO layout for the bottom four rows. The top four rows are always a matrix. If you want more keys, they come in various sizes and bolt together.
Be aware of the significant problem that the programming software requires Windows. It does not run on anything else. The PS/2 connected versions not only require Windows, but 32-bit Windows. (The USB versions will accept 64-bit.) While PS/2 to USB (and vice-versa) conversion works, it does not allow programming. They must be programmed on their native interface. However, once programmed, they stay programmed and can be used on any system or any OS, and either interface type.
Another option is the Cherry boards I posted elsewhere, though they don't have nearly as much customization ability as the Tipro.