Actually, there are a couple of small drivers available. Mountain Electronics carries 10mm drivers, or you could build one from the Oshpark thread. There is a tiny10 that uses 105C driver components, or Teeny10 that is only a contact board and a pad for a single 7135. Then, there are a couple different direct drive 10mm drivers as well. I think all of these are also available in 12mm, except for the Teeny10. Everything you could ask for. 