I just got off the phone with soundgate (www.soundgate.com) and discount car stereo. Both currently have cd changer adapters for I-bus stereos and are expected to have adapters for A-i bus next month. Soundgate said it should cost about $150 and Discount Car Stereo said about $60.
For those folks who don't already have a CD Changer from before, its probably better to go OEM ($429 I think) but if you already have an Alpine or Sony, this may not be a bad option.
The soundgate folks said they are just reprogramming their software to accomodate the A-i bus stereos. Both companies said that the A-i bus adapters were really not a problem and they will definitely have them very soon.
Hope that helps people who already have a changer.