I can confirm that iOS 7 BETA 4 has fixed this issue. If you are using the RN 42 APL bluetooth chip (which you must be as its the only one available on the MFI program)
The only thing you need to be aware of is that the firmware on the RN 42 module needs to be 5.36 and above (as it fully supports the iAP protocol)
I have updated my App (that talks to a custom build accessory) and the accessory picker dialog works a charm.... just thought I'd let you guys know!