Wondering if one could practically implement a site with TLS+SNI for browsers that support it while letting browsers on XP and others that don't support it hit

Wondering if one could practically implement a site with TLS+SNI for browsers that support it while letting browsers on XP and others that don't support it hit the site with HTTP unencrypted. Of course, not appropriate for all sites, but definitely a step forward for sites holding out due to incomplete support.