Yes. tmpfs filesystems should be creatable by unprivileged users and mediated by file descriptors.

It should be possible to mount them (through both mount mechanisms and directly or indirectly via FUSE) and to pass them through pipes (by descriptor).

It should be possible, with an open filesystem fd to get dirfd streams and do whatever operations one feels like through openat & friends (here comes the indirect FUSE support path).

This would be a sensible way of finally solving the main problem of UNIX pipes & structured data interchange.