If you're looking for the Happ Low Profile illuminated buttons, Divemaster127 has them
here.
PROTIP: They come with #161 bulbs which you can swap out for standard LED button LEDs like
these, but not for the
super bright SMD LEDs which are too large.

Arcadeshop.de has Sanwa OBSF-24TR buttons in 4 colors
here.

Both sites mentioned above also carry square and rectangle buttons.

NOTE: Happ low profile triangle buttons have a smooth finish on the button bezel, but the Happ low profile rectangular buttons have a textured finish on the bezel.

Scott