Congrats on the Filco Brown Tenkeyless!
The blanks are available at Elitekeyboards. Complete review and key changing instructions here. (http://geekhack.org/showwiki.php?title=Island:6511)
Blanks are fun but ya gotta be prepared to really learn the diacritics!
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(http://geekhack.org/attachment.php?attachmentid=3263&stc=1&d=1248194571)
im all set with those. ive been using blank keyboards for quite some time. the only trouble i have is some typing one handed.
i actually picked up the otaku tenkeyless so im all set on blank black keys, i was hoping to find some funky colored blank keys or with pictures that would fit the cherry switches. ATM, i'm thinking of filling the zxc and qwe rows yellow, and leaving the rest black but i'd be open to any other funky options.
ps: tenkeyless rocks. i actually could use a numpad, so i got a numpad too and keep it on the left. also, after using these browns for a bit, i'm not sure i'm interested in sampling (or at least paying for the privilege) blacks or reds. browns seem great