I have had that setup before, works well. I was going to try to use LSNAT because I wanted to LB our AD servers also, and I want to use NAC as a test. Basically, we have had several DC outages and it takes a little while for NAC to try another AD server for authentication. So LSNAT would take care of that and also spread the load out over our AD infrastructure so all auths aren't hitting our primary AD DC. I am about to turn 802.1x on everywhere, so LDAP auths are about to go way, way up. Just want to make sure everything is evenly distributed and failures are transparent to users before we flip the 802.1x switch on all wired ports. Otherwise, 802.1x in my testing is working flawlessly.