So far, we have:
SKCL/SKCM — "regular" Alps
SKFL — corned beef tin Alps
SKE? — semi-integrated dome
SKFR/SKFS — those other ones
Maybe I should offer a prize to the first person who's able to get the series name of the "vintage tee" ones. The series name for SKFL came off a label affixed inside the keyboard itself: "normal" keyboards have part numbers beginning KCL/KCM/KFCL/KFCM, and then Nubbinator found one with a code beginning KFFL:
http://deskthority.net/keyboards-f2/alp ... t7619.html — thence the confirmation that they're SKFL (from a sadly now defunct website, Technology Transplant, that was selling spares of them, who are now uncontactable by anyone).
Integrated dome also appears to be SKE? but we don't even have the third letter yet for a tee mount keyboard:
[wiki]Alps keyboard codes[/wiki]