It's a Chatterbox Falls model Sundowner
Somewhere on another computer, I actually have a sales brochure on the Chatterbox Falls model. Basically it's the 30 footer with raised pilothouse and owners berth, but nothing behind the original version as sold by Sundowner. I'm betting that someone later added the galley and rear section. BTW, those pilothouse doors are not original either. If you're really interested, I could dig up the brochure.
RickH (also a Sundowner 30 owner)