Where can I find a list of doctors/physical therapists that do functional rehabilitation for Achilles Tendon Ruptures?

Online. You may do a quick google search for Orthopedic or Urgent Care centers online for a provider near you who may help. Otherwise, call your insurance provider or visit their website online for a list of covered providers.
Majority. Almost all certified physical therapists would do functional rehab for Achilles' tendon ruptures. It is a fairly common injury and therapy is used in most cases. Not really a specialized area at all.