Never say “no,” but as of now there seems to be no agent able to do this.  In fact, we are almost certain one can’t…but let’s hope that changes soon.  You will not be able to travel overland from Western Sichuan into the TAR via land without the appropriate permits.  The best place to organize your permits to visit the TAR is in Chengdu through a travel agent at least 2-3 weeks in advance.  You can organize a TAR trip easily through www.extravagantyak.com.