Progress appears to be continuing at the OpenBSD project w/r/t UEFI support, with multiple devices!
Jaspar has a new blog post with information on using OpenBSD on UEFI-based systems.
http://blog.jasper.la/openbsd-uefi-bootloader-howto/
http://undeadly.org/cgi?action=article&sid=20150902074526&mode=expanded&count=6