I've played around with this some more (on Ubuntu), but I'm not really getting anywhere. I.e., with my perl-5.10.1 I somehow can't get the Fuse module to work:

~/PM/build/Fuse-0.09$ make test
PERL_DL_NONLAZY=1 /usr/local/bin/perl "-Iblib/lib" "-Iblib/arch" test.
+pl
test/s/mount.t ... 1/3 # mounting examples/loopback_t.pl to /tmp/fusem
+nt-almut
# Mounted in 0.2 secs
test/s/mount.t ... ok   
test/chmod.t ..... sh: cannot create file: Function not implemented
...
...
Failed 7/21 test programs. 45/156 subtests failed.
make: *** [test_dynamic] Error 255
[download]

And I don't really know why. Doing exactly the same steps with perl-5.8.8, all tests succeed (but this is of no help here, as it's the 5.10.1 that has the 8k buffer...).  Also, my 5.10.1 is generally working fine (all tests did succeed), as is my system's fuse.

I think I'll give up for now... :(  Sorry.