Interesting idea. It's worth mentioning that one file in Cappuccino means one file per bundle, plus the index.html file and Objective-J.js.
A typical app has the Cappuccino bundle, and one bundle for the app code, but using an external framework means adding an additional bundle. We're exploring techniques to further concatenate bundles together (we have one in the project, but it has some negative side effects).
I'm curious about your concatenation technique. Dynamically creating multiple script objects (with document.createElement) from a data file and injecting them has been reasonably robust for me but I'm not writing a framework so I have far fewer test cases! :-)
Cappuccino has a completely custom loader and concatenated file format that creates a file system representation, such that when you do something akin to XHR("something/blah") it knows that it already downloaded it and gives it to you without a request, that way whether you ship concatenated code or not the code that fetches it is the same.
A typical app has the Cappuccino bundle, and one bundle for the app code, but using an external framework means adding an additional bundle. We're exploring techniques to further concatenate bundles together (we have one in the project, but it has some negative side effects).