Hi Tim,
that brushed face plate looks pretty good!

Sorry I've taken so long to get back to you about the buttons. The Farnell part number for the standard black buttons from the Mark I is: 917-461 and they cost 56 cents each, with a minumum order size of 10. The caps with the lens in them (# 311-2457) don't cost much more - 61 cents each, and you can buy them singularly.

Now what is really interesting is that there are some shaped button caps, so you don't just have to have boring old round buttons, and they come in 4 colours! There are square caps, round caps and arrows in blue, grey, red and black. The one problem with them is that they are only the standard height, not the extended buttons like we have, but alongside the standard Mark I buttons is an extender that may be what we need to get them to work! Now I really wish that I had scanned in this page when I was at work so that you could see for yourself!

Wait, they are Multimec 3F series switches - there must be something on the web
the manufacturer: www.mec.dk
(hey, I don't have to look any further here, they even have CAD drawings!!)

And, looking at the tables, the nicely shaped caps work out about the same height as the Mark I caps when you use the 5mm extender. Cool! Hmm, unfortunately Farnell only list the 10mm extender :-(

(another picture of the round red caps with extenders: http://www.solico.com/new_products_from_mec2s_ser.htm)