Yes, the very first one on this list, .ac

http://en.wikipedia.org/wiki/List_of_Internet_top-level_doma...

  # dig ac.
  
  ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-16.P1.el5_7.1 <<>> ac.
  ;; global options:  printcmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37041
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
  
  ;; QUESTION SECTION:
  ;ac.                            IN      A
  
  ;; ANSWER SECTION:
  ac.                     86400   IN      A       193.223.78.210
  
  ;; Query time: 173 msec
  ;; SERVER: 10.0.80.11#53(10.0.80.11)
  ;; WHEN: Thu Dec  8 11:37:09 2011
  ;; MSG SIZE  rcvd: 36

I'm not going to go down the list and try the rest.