Hi everyone,
I'm one of the developers at niftools (see my signature, mirex maybe remembers me), and I accidently stumbled on your forum; very nice work you guys have been doing here!
I'm working on file formats myself as well, however since almost two years so I've taken a strong focus on interfacing them in order to create custom content, not just in the nif format, but in any block structured format that admits a simple enough (i.e. block structured) file format description.
In particular, besides the nif format, I've also decoded most of the cgf format for Far Cry and Crysis, helped by Crytek's mod sdk, and I managed to support both nif and cgf formats on Python via a single unified library called "PyFFI", which stands for Python File Format Interface. The reason that people here might be interested in this, is that it's extremely easy to add new formats to the library (the main difference between the nif part and the cgf part of the library is the file format description, which is written in xml, and this description format is very easy to learn). This is the main point of why I wrote PyFFI, and it turned out to work rather well. I found it useful for decoding formats as well, as it is easy to display analyzed data with it (in a nifskope-like fashion, if you'd be familiar with that).
So if anyone here is interested in interfacing file formats with minimal coding effort... yet another tool at your disposal. See my signature for the link. I hope it is useful.
I was also wondering how you guys went about interfacing new formats. I'd be happy to learn from fellow decoders how they go about this.
Cheers,
Amorilia
EDIT: not sure why but my signature is not attached, so here are the links:
http://niftools.sourceforge.net
http://pyffi.sourceforge.net