If you have Office 2010 installed you should find an msapps12 namespace on your machine.
The classes exposed by this namespace can be found with
Get-WmiObject -Namespace root\msapps12 –List
There are a lot of them! The classes seem to be broken down by Office application for instance to see the classes for dealing with Word documents
Get-WmiObject -Namespace root\msapps12 -List *word*
I can’t seem to find any documentation for these classes so a bit of trial and error is involved