Perhaps this is nit-picking but there is a syntax error in SL's /etc/redhat-release:

Scientific Linux SL Release 4.0 (Beryllium)

According to the man page lsb_release(1), "release" must be lower case:

> The required line style is:
> "Distributor release x.x (Codename)"

It could be significant for a script trying to work out what distribution it is running on.

Cheers,
Morten