I know that Felix Kronlage, the OBSD developer in charge of the OpenVPN port, uses it.
In Belgium in 2006 , when I was assisting in shipping the OpenBSD 4.0 CDs , I have seen him log in to one of his customers machines in Germany with OpenVPN.
For a log of recent changes in the OpenVPN port see
http://openports.se/net/openvpn.