It would be so much easier to make an SP App if there is a good SP API. Oh my gosh I would loove to see a good SP API!
I have created a client side API for the bulk uploader...it knows how to search, to post photos, to delete photos. But the code is ugly because it is "from the outside"...basically it's parsing html and putting an API facade on top. If I could throw that ugly parsing code away, the bulk uploader would be a lot simpler (and easier to reproduce on other platforms that I haven't had time to do, like the Mac).
Matt, I'd love to work with you on an API design and even coding for that if you'd like.