Well, I'm doing it, though that may not mean much, as I'm the one who contributed the RPMs. MySQL is a stock MySQL RPM; there have been no changes to it for e-smith. Same with Apache (but use the 1.3.12 RPM, not the 1.3.9 that comes with e-smith).
AFAIK, the only limit on how much traffic e-smith can handle is the hardware--you obviously wouldn't want to run a server like you've described with a P75 and 16 MB of RAM. However, Linux and Apache together are very stable, and capable of handling very high traffic loads (IIRC, Deja.com runs on Linux and Apache, to name one).