Hahaha, I must be hallucinating!
Yes, the Elk M1 supports Radio Ra2 - http://www.elkproducts.com/product-catalog/elk-m1xslu-m1-to-lutron-radiora2-serial-interface
So here is an interesting situation. If HS3 supports Elk and Elk supports RR2, does that mean I can control my Lutron lighting...