[Plash] Can't use plash for read only yet?

[Jago Pearce]

I see read-only access isn't available yet... so I can't use it to have all 
ssh logins over ppp0 (or all except 192.168.1.0/24) use plash shell instead 
of bash, so I can login to home from work to view files and stuff.

I could create a new user but I think I'd have to have a copy of all files 
(not really workable), and I don't think I can link files and change the 
link permissions either