Here's my idea.
You want a vertical truss? simple - construct a horizontal triangle, attach a balloon to each corner, attach a wire from each corner of the triangle to a corner of the truss.
Dangle a weight from the bottom of the truss.
You could also have a cable from each corner of the bottom of the truss to the triangle to stop the bottom swinging - though news items mentioning LOHANs swinging bottom might be worth reading.
The triangle will have to be large enough to allow LOHAN to pass between the orbs of course.
Similar to above but with one (or more) balloon(s) mounted above the triangle. truss could then be angled as needed by tightening one of the lower wires (bottom of truss to triangle).