Thanks Buzz, that is a most welcome add-on! I've been wanting one of those since Marias Pass first came out.
There's plenty of GN F-units available for TS, but they only work for post 1950s Empire Builder lashups. The E7s went on pulling the new Western Star for quite a while after the F-units had taken over the Builder, so that's a very useful repaint indeed.
Are you taking requests?

The E7s also got painted in the really not so beautiful Simplified EB livery. While this doesn't fit into the Cascadian route's time frame, it would go well together with other GN repaints. There a good picture of an E7 in that livery near the end of this page:
http://www.gngoat.org/diesels.htmCheers
Michael