hmm that is weird.
Here's what I'm almost positive they are doing:
one pin on the end is shared with all the others, and the second end of the reed is the single soldered one you see under each switch.
So you get sort-of and odd matrix, and possibly only 1kro down each of those switch blocks. I can come up with a diagram on how to wire it up when I get home tomorrow.
Y, that's kind of my take on it. The switches are actually physical columns, so I would guess one contact at the bottom would be "common" to all in the column and the other one of the pair and the single ones of the other switches in the column make contact with the common line when the switches are pressed. You can check this pretty easily with a multimeter / continuity meter.
Actually 1KRO per column kind of makes sense if you use it in the correct orientation. You're not likely to press more than one key with the same finger on purpose and most people wouldn't use 2 fingers for a column.
If the switches feel nice, then by all means wire them up to a Teensy and make a nice little custom numpad. It would be quite unique
You can probably desolder the columns and glue them to each other so you don't need to make a plate or anything. Just some kind of housing to protect the contacts and the wiring and mount the Teensy. That's what I'd do. You could also use a few of the 7 segment displays mounted in the case and program the Teensy to display cool stuff when you press each key, something like the Predator's arm display. Or the boring version is to display the actual character pressed.
Another option is to code the algorithms for actual calculation into the Teensy, so as long as it has power it will function as a (rather limited) calculator. Lots of cool options.