I'd love to see an alternative to doing this with Excel, maybe that will be the next enhancement to Orion NCM!!
That being said, I have thought of doing what it sounds like your Network Architect has done, and still might do it. Would love to see him publish something on his work.
But, I think you'll see I now take this on a slightly different bend. And rather than dropdowns, I'm using INDIRECT() references to a sheet that probably looks familiar. The "Sites" sheet in this example should look like one of many project sheets you might have used along the way for big projects where you configure a bunch of routers, but want a central place for the information upon which those configurations are built. By using the INDIRECT() function to build my "Variables" sheet, we can build multiple router configs easily without having to enter any data twice.
My latest BLOG entry takes you through the setup of this Variables sheet, which will then be used to configure up multiple routers and IPSEC/GRE tunnels on your head-end router (in the next Blog post).
So check it out and let me know what you think of my latest Blog entry on "Preparing to build a cisco config with Excel"
http://the8thlayer.blogspot.com/2015/11/preparing-to-build-cisco-config-with.html