What characters should be allowed in a MIME subtype?

Hello,
it's nitpicking time again.
I looked at the definitions for the "subtype" of the MIME type/subtype
tuple. It's a TOKEN, and a TOKEN is 1-many of any CHAR except SPACE,
CTLs or tspecials.

So, the following characters seem allowed:

A-Z a-z 0-9
! # $ % & ' * + - ^ _ ` | ~ (ASCII - tspecials)

So, an example of a legal subtype would be

harald's&alf's_very_interesting+morally_indefensible_subtype#1289!!!!

That's very nice for demonstration, but maybe we would like to tighten
this up a bit for the next revsision?

I personally would be happy with A-Za-z0-9, - and +.

Comments?

                 harald Tveit Alvestrand