DC,
Just as a FWIW exercise, I visited the Nexus site and did a "Design Your Own" exercise putting together the closest Nexus model (25P) I could to our old 2005 Itasca 24V Spirit (sadly, Winne no longer offers a modern day equivalent model in the short lengths).
Our Spirit came from a dealer's inventory with a lot of options - including the E450 chassis - so I had to add options to the standard 25P in order to get a close as possible matchup. The 25P seems to come only with a slide, which we do not have.
Here's a link to the ancient brochure on our 24V:
http://www.winnebagoind.com/resources/brochure/2005/05-Spirit-bro.pdfThe brochure seems to imply that the Spirit's super structure contains only steel (coated via an electrodeposition process) and aluminum (no wood?). Thanks to our negotiating luck and inflation our 24V, new, of course cost us way less than a current new base 25P.
P.S. I must have too much non-RVing time on my hands! :)