There is a sambo position that I think may be called a "Russian knee bar" - it's sort of like the knee knot done from the saddle. There may be videos of it out there.
Someone visiting showed it to me last weekend - at first take, it seems pretty dominant, but the thing that Alex Canders pointed out is that it makes it tough/impossible to get your own knee to the mat in the saddle, which makes it easier for the uke to stiff arm your knee and start to work the escape.