Orlando Padron once told me tht the tobacco in the 26s is the best Padron produces and is aged at least one more year (a minimum of five years) than the 64s. In my opinion the 26s have a thicker, more full bodied flavor. As a result many people prefer the taste of the slightly less expensive 64s.
This past weekend while visiting a very reputable B&M in Austin TX, a Store Rep told me that a Padron 26 is a different blend than the 64's, but if you take a regular Padron and age it for at least 2 years, you will then have the same cigar as the 64. Supposedly this info came from a Padron Rep. Of course I don't know if it's true or not true.