You could do it with multiple manufacturers really. I like my Glocks, but they certainly haven't cornered the market on multiple calibers all with the same operational functions.
With that said, try qualifying with a Glock 9mm and then jumping to a 10mm.
Unless your qualification is a single round sequence, i.e. no double or triple taps, I guarantee that you'll struggle a bit.
@Boats - ever qualified on a two-way range? How high was your hit percentage?
IIRC, there's an FBI study that says the average LEO gets 10% of his or her rounds on target in a firefight. If you're carrying eight or nine rounds, that's less than one round on target per magazine.