Making a Cambooth for your Lyft

I'm beginning the process of figuring out how to make a cambooth for my lyft car.  Process and all code will be open-source and shared at https://github.com/ityonemo/lyft-cambooth

This is inspired by the guy who did it at sundance - but cheaper!  and open-source.  (https://www.youtube.com/watch?v=PTlf5of9q4M)

Current choices (suggestions/comments most welcome):

Raspberry Pi (~$26)
Raspberry Pi camera add-on (~$36)
miniature wi-fi stub (~$10)
(use phone-based wi-fi hotspot - will be testing with sprint/android/cyanogenmod combo)
A cheap LCD screen (various, ~$20)
Sinatra (http://www.sinatrarb.com)-based webserver, localhost server controlling logic (to cut down on data transmission) (~$0), openshift or heroku remote server to store and allow users to download their pics. (~$0 for endusers)

Open problems:

How to hook up to a car power without awkward cables all over the place.
Will we need a flash?  How do we do this?
How do we mount this inside a car?

Bonuses:

Having a Raspberry Pi inside your lyft can enable some really cool features; so there might be some side development of cool things, like, mood lighting synched with the music.