There are many people already converting their radios to DX6 with DX6 components. It is super easy as I have already done it myslf with my Optic 6. Other radios I've seen converted are JRs and a Hitec Eclipse.

The wonderful thing about the DX7 is that people who upgraded from a DX6 are willing to get rid of it cheap to help pay for the $350 DX7. I bought my DX6 from a LHS for $50, gutted the one part I needed and made the upgrade. Super easy, superfast.

I used do-it-yourself servo connectors. This enables to go back to FM anytime.