> Currently it is possible and often applied practice, to use > \( \mathit{\Gamma} \mathrm{\Gamma} \mathsf{\Gamma} \) but that only works (with the current definition of \mathxx) because the upper case Greek is in the text fonts. So it would not be sufficient to make these variable family (ie letters) they would really have to go back into the T1 encoding, which surely no one wants. In particular the above does not work even now if using anything other than cm as the text fonts, as no other fonts have Greek, and normally fontinst choses not to attach Adobe symbol greek onto a random text font and so these slots are empty. It is possible to devise commands that take a command such as \Gamma and then to typeset a symbol from a different family without relying on the \fam mechanism. See for example \bm from bm.sty. \bm{\Gamma} (and \bm{\gamma}) make bold letters but if suitable fonts were available something similar could be done for other style changes. So even with Gamma and friends being assigned to a fixed family, one could still produce an interface to switching and `for compatibility' that could (perhaps) even optionally be hidden under a more complicated definition of \mathxx David