In one of our previous blog posts, we demonstrated a proof-of-concept of an AoE WAN tunnel. We have now produced an application note delineating the process used in the test. Here is the link, which will also be listed on Coraid's recourses page.
http://www.coraid.com/site/co-pdfs/AoE%20WAN%20with%20GRE%20and%20IPSEC.pdf