Well, it does - as long as you call statvfs directly with your own program, of course.
Or if you use "/usr/bin/df" rather than "/usr/ucb/df" - Sun don't appear to have "improved" the standard SV "df" command not to report on inodes on NFS-mounted file systems the way they "improved" the BSD-compatibility "df" command. (Of course, it reports -1 on V2-mounted file systems, as the V2 protocol is busted and has no way of allowing a server to report to a client the number of free inodes, but it works, as far as I know, on V3-mounted file systems.)
I just commented out the df -i check in inn and made sure I had enough inodes on the filer. I didn't pick a *huge* value, but about double what I needed.
Yes, this is what I'm currently doing.
One could also possibly mount the file system twice - once with V2 and once with V3 - and use the V2-mounted file system for all but checks for free inodes and use the V3-mounted file system for the latter. (You probably want to avoid accessing *files* on both file systems, as the client won't know that file XXX on one NFS mount is the same as file XXX on another NFS mount, and could get confused.)