Hi guzzi
For what I hear from some developers, creating an File System driver is not a nice task especially because of the extensive testing that this kind of drivers requires.
What it will be great as a start is to have the eCS-OS2 implementation of JFS-boot complete open sourced. I asked that once to Mensys and they told me that the source code of it was provided in part by IBM, so they can not release it, which it seems odd since IBM released JFS as open source to be included on Linux, but who knows.
What I would think it can be good is to try to move away from HPFS, since MS owns the patent of it, and that is why (in part) several companies dropped HPFS support from their Partition Manager tools (I remember that Partition Magic killed HPFS support since version 7). I don't know which file system is the best, but I will not like to go back to one with patents that can produce more risk.
I know this is not a priority right now, but it is a good exercise to think about file systems from time to time, thanks for bringing it.
Regards