I don't think that this approach would work. Google's John Mueller said that Google uses sitemaps as one way of recognizing which URLs are canonical. If a URL were in your sitemap, but had a canonical tag to a different page, you would be giving Google mixed signals. Its not clear which page would win the canonical battle.
The outcome almost certainly wouldn't be the effect you are looking for of having one URL used as the content and the other used as the landing page.