FYI, to anyone who was considering using "puppet", but had to resort to alternative, or hacky, methods of managing SMF properties:
I've just written up some native puppet support to do so.
I dumped the initial code in the puppet-dev mailing list.
May or may not get around to making a nicer version of it. But for those who'd like to use it, here's a ref for ya:
http://groups.google.com/group/puppet-dev/msg/777cc63c48438891?dmode=print
This lets you do things like use puppet to force
svc:/network/smtp:sendmail config/local_only = true