deskthority

So that switch I linked to, is a completely different colour, just for fun?

Pretty much.

Those switches just get worse and worse …

The beige switches are used for wide, long and large keys. This is the case with the Kaypro keyboards, including space and return on yours (above) and the wide and long numeric keypad switches in SMK and Maxi Switch Kaypro keyboards (below) and your TTX and Geomet keyboards:

http://deskthority.net/photos-videos-f8 ... t5563.html

The BBC Micro Type 4 keyboard (made by AWC, switches confirmed SMK) uses beige+black switches for just space bar and return:

http://wouter.bbcmicro.net/pictures/com ... _front.jpg
http://wouter.bbcmicro.net/pictures/com ... index.html

The type 2 keyboard (made entirely by SMK) used beige+brown+black switches for the wide keys, specifically left and right shift, tab, space bar, and (seemingly) return:

http://8bs.com/see/b2key.jpg
http://8bs.com/see/b2key2.jpg
http://8bs.com/insides.htm

(I can't quite tell what's under return)

I don't know what's different about the switch, only that this is clearly the intention. It's interesting, as I've never seen this pattern with any other switch type. I know that the wider keys on my Tulip 2nd gen SMK keyboard have binding problems; if this problem goes back to the 1st gen, SMK could have found a workaround that necessitated special switches for wider keys. It's interesting that AWC didn't seem to follow the pattern. The problem my SMK keyboard has have could be age and wear, as nobody else has ever reported this failing with SMK switches.

Also, we need to get more dates ..... from Maxi Switch keyboards. Those Kaypro keyboards are 1984, as is the Geomet 200.

Actually, wait — the M0110A used them, and that wasn't made until 1986. That explains why those have the current SMK logo, and it also fills the gap between 1984 (previously last-known example) and 1986 (earliest known 2nd gen).

alps.tw reckons 1989 for his M0110A, although the case stamp is clearly set to "90":

http://kbtalking.cool3c.com/article/29020

So yes, the SMK and Maxi versions clearly overlapped: there was no transition from one to the other.