Hi Ian and LO (and any other which I’m unaware of)
Surplustronics have some VERY nice illuminated buttons at the moment for only $2 each. They are similar to the transport controls that Alex has on his LC clone.
RS cat# 339-342
They dont have the coloured caps included but they are avalible from RS for about $1.90 each in Red, Blue, Green, Orange and Opal
Only problem is they are quite deep (approx 35mm).
They have about 15 left, so get in quick.
Cheers
Rowan