Variphrase technology is the major contribution of the Roland VA-7 to the arranger community. The Solton X1 introduced live drum loops to arranger styles. The Roland VA-7 extends this to include pitched instruments. In terms of audio data, as opposed to midi data, the Solton X1 is like a drum machine and the Roland VA-7 is like an arranger keyboard. An arranger keyboard can do everything a drum machine can do, but handle pitched instruments as well as unpitched instruments. (IMHO, musicians that accept drum machines as legitimate musical instruments but regard arrangers as toys are somewhat hypocritical.) The analogy is not perfect, since an arranger keyboard recognizes harmonic relationships, while I do not believe the Variphrase technology (as currently implemented) does.
I have watched the Roland Video Demo of the Variphrase VP-9000, and had been considering its implications for arrangers when I read Yves notice of the VA-7. Consider the following. Sample a vocal phrase from a favorite song into the VA-7. The vocal phrase with have some rhythmic elements, pitch elements, and various nuances. The VA-7 will process this vocal phrase to extract the rhythm, pitch and nuances separately. Now play a midi-based style with the left hand and a melody with the right hand, selecting the vocal phrase as the right hand instrument. The right hand will generate the vocal phrase, but the melody will follow the keys played by the right hand rather than the original melody. However, the timing will match the style. All the original nuances of the vocal phrase will remain. You can play 2-6 parts polyphonically for harmonies that match each other and the accompaniment style.
Furthermore, you can have two vocal phrases, originally in different keys and with different timings. These can be played together (either in unison or by splitting the keyboard), so that that the phrase match the accompaniment rhythm. However, each phrase will retain its original nuances. For example, the separate identities of male and female vocals can be maintained. I choose vocals as a particularly difficult instrument type for styles, but the same technology applies to any instrument. Is anyone else excited about this?