[jcrawfordor]

I regularly use what I call a "140% keyboard" which has a total of 140 keys. This is the regular 104-key layout with added keys in various places such as between the alphanumeric and F key section, filling the gaps between cursor keys and the block above it, etc. The keyboard has on-board macro programming and multi-layer logic.

I use it for things like having keys which jump directly to specific windows, keys which open various terminal types, and even macros for some common commands (Git operations for example).

I don't know that there's any good reason why this isn't more popular other than fashion, which means that an industry has not really built up around plus-sized keyboards like it has around smaller ones. My example was purchased used and was formerly used at a telephone operator's workstation, based on the key legends. There is a fairly robust used market for plus-sized keyboards originally used for specialty applications, mostly POS and dispatchers/radio operators, from companies like PrehKeyTec and Cherry (of the switches). Unfortunately they mostly cost $500+ new and still often demand over $100 used. The majority of these keyboards feature on-board macro programming, but are intended to be programmed in bulk by the vendor of some turnkey solution so the programming tools are a bit awkward (for me, use a GUI keymap editor, export a file, use a command line tool to flash the generated file to the keyboard - I think it actually just produces a full firmware image each time).

The only real disadvantage I would report is that the PrehKeyTecs are made with dome switches that feel decidedly mushy when they're old (and my used model is probably around a decade old). The Cherries use mechanical switches, of course, but tend to be more expensive and aren't made in as interesting of configurations IMO.

[mindslight]

Do you happen to have a picture of the layout? I too wish for a keyboard with more keys, especially vertically. But besides an extra row or two of F-keys, I haven't come up with any logical extensions.

[jcrawfordor]

It's a variant of the PrehKeyTec MCI3100. Photo: https://www.prehkeytec.com/fileadmin/user_upload/global/prod...

Note the blanks in the lower right there do have switches under them so you could put keys there as well (that's where mine has Hold and UnHold incidentally). One warning is that the blank keycaps and relegendable keycaps (the ones that are a clear plastic cover you can stick a bit of paper under) are mostly sold in bulk to system integrators and it's expensive to get them in small quantities. So if you're in the market, you probably want one with as many of those as possible. PrehKeyTec's software supports printing legends for them but it's pretty basic so you might want to use something else to design them.