Our N scale layout at the Golden State Model Railroad Museum also models Tehachapi pass. The loop is a fairly faithful reproduction, I love it. The layout models both Tehachapi Pass and Donner Pass, (although neither of them very faithfully, I must say, aside from the loop.)
We do need some better pictures on our website...(if you look at the picture on the N scale page, which at least shows the whole layout, you can barely make out the Tehachapi mountains at the very back of the photo).
EDIT: Gary, just saw you already mentioned it for us, thanks! And BTW, that's an awesome awesome track plan. The kind of thing I dream about. Can I come see it when it's done?