Gentoo and glibc 2.1.3.21

Hello,
I've installed Gentoo quite a few times but now I've got a new twist so I
figured I'd post to the newbies section first.  At my new job we all use
linux and RH 6.2 is the standard distro that comes standard on your machine
on the first day.  We're allowed to change and configure and customize
anything we want as long as we keep glibc at 2.1.3.21.  Now I don't think
they expect many people to change to a completely new distro but frankly I
miss portage and a nice lean optimized machine.  I'd like to install Gentoo
(especially since it is a dual athlon machine) and see the speed of
compiling everything optimized for this particular machine.

The question is could I install Gentoo with glibc 2.1.3.21.  I don't even
see any ebuilds prior to 2.2.x.  What are the major differences between 2.1
and 2.2?  Is it even worth going down this road or am I just asking for more
trouble than it is worth?

cheers
chuck