The short answer to this question is that there is no "easy way". Yes. a FEW (and the key word here is "few").. have successfully packaged Office 2007 or Office 2010 over the past half-dozen years.
My personal suggestion is to put the installation media image on a read-only no-authenticated-required file share, and then build the package to ship only the setup.exe to the client. Launch the setup.exe using the network share as the installation source.
(One note on the Office 2010 article that David cited... it has a broken link to the MST Transform article. I'm working on getting that fixed.)