I believe this is actually in E with a series of substitutions forming a variation of what is commonly referred to as a Tadd Dameron or Lady Bird. Here is an excerpt of a general article about turn arounds found at http://www.allaboutjazz.com/articles/ji0898_01.htm

With all the substitutions you are actually spending more time in a C tonality.

The changes are E Maj7 C Maj7 a min7 F Maj 7
the a min7 is the variation, also there is another passing chord left out which would be G Maj7 after the E Maj7

The Tadd Dameron "Turnaround"

There are other chord progressions that can be used to provide a "turnaround" or transition back to the "I" chord. The following "turnaround" is sometimes referred to as a Tadd Dameron "turnaround." This "turnaround" is an identifying harmonic element of the composition "Lady Bird" composed sometime in the 1940s by Tadd Dameron, and recorded by Miles Davis and Charlie Parker among others.

I Maj. - bIII Maj. - bVI Maj. - bII Maj.

In the "Tadd Dameron turnaround" the "I" chord ascends a minor third interval to a Major 7th chord built on the flatted third degree of the tonality. The "bIII" Major 7th chord ascends an interval of a perfect fourth to the "bVI" Major 7th chord, and the "bVI" Major 7th chord ascends an interval to the "bII" Major seventh chord.

The "bIII", "bVI" and "bII" chords are tritone substitutions for the "iv7", "ii7" and "V7" chords respectively that compose the basic "iii7-VI7-ii7-V7" basic "turnaround" described earlier.

cool thanks for sending out that link to solfege.org I think I'll start a thread for it