Well.

If you really want to create a SLES' clone, you can. Since SLES is just a more mature clone of Opensuse, all you have to do is to clone Opensuse.

You can also DL SLES and update your whole system with opensuse's repo and it's pretty stable too if you take care about what you install.

And don't forget one thing: SLES and RHEL aim two market.

SLES, with trade agreement with MS and better proprietary support, aims enterprise who want to get rid of MS without risking too much.
Logically, the product that Novell's offer is less open.
And please takes note that SLES' sale have climb in a faster manner since the agreement with microsoft.