For a recent project, I tried something different: running two themes side-by-side on the same #WordPress site using #ThemeSwitcher Pro. The unusual part is that both themes shared a single header.
Read on to learn about the architecture and some "gotchas".
carriedils.com/one-header-t...
How a legacy WordPress site moved toward Full Site Editing without a rebuild: two themes running side-by-side, one shared header, no content freeze.