So it turned out that the 'ar' 'common' format, which is what 'deb' files are, is trivial. It's essentially all of the files concatenated, with some metadata prepended to each file.

http://en.wikipedia.org/wiki/Ar_%28U...format_details

As a result, it is fairly straightforward to implement it using cat, printf/echo, ls+awk / wc to get the file size, and expr to do modulo-2 on the file size, because file entries have to be 2-byte aligned.

I was delayed in several ways today which kept me from getting this done sooner, but now I bring you: fkdep

Ta-da. It'll install packages with the name fkdep-[fake-provided-package-name], assuming it gets root permissions to do the actual install, or, if run as not-root, simply generate the .deb file and then leave it in the /tmp/fkdep-[whatever] directory for you to do what you want with. (For extra amusement factor, the fake packages self-license themselves under the wtfpl )

I'll make a proper announcement thread when I've had the chance to package it for our repos here.

[Edit: To be clear, this has, near as I've tested, literally no dependencies besides what is already installed on an N900 stock. I tested all of the individual commands through the stock busybox, BUT I have not yet tested on a truly-stock, no-CSSU-or-anything N900. It's on my todo list to do that, in the meantime if someone does find an unnoticed dependency let me know, though I'm fairly confident there are none.]