I found these links to a guy that made a custom AC system for a Series 1. It looks like he copied the Delanair design. The first link has some great shots of how much needs to be cut out behind the dash.
The second link has some other Series 1 modifications that he did.

http://www.facebook.com/pg/Jollywren...19343311634318
http://www.facebook.com/pg/Jollywren...25220434379943

 

I like the wrapping of the key surround with leather... AC is TOO much.. will stick with installing a VA system in my car.