Matsuoka sensei was the highest ranked in the US till 97 (I beleive) when he moved back to japan, I do not beleive he currently has a tenshin affiliation still. Reynosa sensei had the highest ranking till he recently left the tenshin school.
So to answer the question, I beleive that Santos sensei in florida is currently the highest ranked in tenshin at 5th dan. After that is probaly Angulo sensei and Freeman sensei at 4th dan. There are other tenshin sensei's, but the above are the only I am familiar with as they are directly involved with take sensei on a regular basis. (Yudansan test coming up in november at take sensei's in santa barbara!)
Let me know if I am wrong, because I may well be.