If you are interested in changing your headunit and maintaining your factory dash controls here are your best two current options.

Option 1
Modify has developed a solution that can be purchased through Modifry.com.

No Delays, No Programming and more functionality is what you'll get from the S2000 Multi-Radio Dash Controller Interface (DCI). Have a seamless installation of your favorite aftermarket stereo while ADDING extra functions to your frequently used Dash Controls.

This unit takes signals from the dash buttons, translates them via a microcontroller and beams back via Infrared "eye" to the stereo. Works with MOST listed decks.

Compatibility
SONY (Not compatible HI-R or orbital controller) - If your unit has WIRED input choose the Sony DCI
ALPINE
CLARION
KENWOOD
PIONEER
ECLIPSE
BLAUPUNKT *Must HAVE THUMBER REMOTE UNIT
PANASONIC
ALL DECKS MUST HAVE WIRELESS IR REMOTES.

Functions
Channel Up/Down, Track Up/Down, Mute, Volume +/-, Disc +/-, Band Channel, MODE
(note due to some nuances in decks and remotes not all functions may be present)
Vehicle Speed Adjustment - (installation option- Not needed for all other functions) Increases or decreases your volume corresponding to your
Car's speed - 4 Adjustable settings.

Included
All parts necessary to interface with the S2000 and dash controls are included.
- INTO S2000 Harness (wire color coded for easy mating)
- DCI
- DCI harness with IR "eye"

Option 2
DJ Qube's has developed Audio Controls. You can find detail information along with pricing here.

1) EXTENDED CONTROLS