Yep. You can enable themes on a page-by-page basis.
For anyone who wants to know how, in c5.7:
1. In the Dashboard tab, go to Sitemap
2. Click the page you want, and in the contextual drop-down select the 7th choice, Design & Type
3. In the resulting dialog, the theme selection is at the very bottom.
1. In the Dashboard tab, go to Sitemap
2. Click the page you want, and in the contextual drop-down select the 7th choice, Design & Type
3. In the resulting dialog, the theme selection is at the very bottom.