Using CustomPress with Global Indexing and Search

Planning a new WPMU project and wanted to get some feedback on how this could work.

I am thinking of using CustomPress on the 'user' sites on a WPMU. All will have the exact same 'custom fields'.

What I would like is for each user site to list only their own 'posts' and 'pages' but the top level site (domain.com) to have a master search which searches all the user sites (posts / pages).

I'm guessing this will require global indexing and the global search plugins.

Does the Global Site Search plugin search custom fields?

Martin