This is the knot I posted earlier which I am now calling the "McLoughlin" hitch. Camp Mcloughlin is the Boy Scout camp where I was teaching knot tying when I first tied it.
It is an adjustable loop hitch like the taut-line (midshipman's) hitch. However, unlike the taut-line, it holds its form well when unloaded and works at obtuse angles (can even be used for binding).
I have used it with most cordage (all types I have access to) from dental floss to sisal and found it, once properly dressed, to hold better than the taut-line in every case. The only cordage I cannot verify is some extremly crappy, limp, smooth as silk, no-name poly that neither held onto, but the taut-line did colapse into a nasty mess that finaly caught and held (but was no more adjustable than a Rosendahl afterward).
So, I know most of you have already dismissed this knot, but I wanted to give it a name before I let it die in peace.
K-