If you want to have more luck looking for what you want, I'd suggest looking for a filesystem driver for Windows rather than a format utility. A format utility is quite simple to design in comparison to getting the OS to use the partition safely

I strongly doubt you'll find it for Windows. Some UNIX variants have at least Amiga FFS support (warning: the name Fast File System isn't just Amiga-related).
I'd suggest getting WinUAE to use a path as a volume on AmigaOS under emulation, then when you want to 'put it back' in your Amiga, network transfer via FTP or something.
- edit - Oh, I should have said - if Windows can't read the filesystem, it won't mount it as a drive. So cast aside thoughts of partitions only being readable in WinUAE :-)