Some more experimentation in this one. Thoughts? Gobo'd flashes mean that I have more freedom to hold the balloon without interfering with the shot. Had to do this a good few times to get the timing just right.
Strobist: SB600 on camera left and below, gobo'd, on 1/64th power. SB800 on camera right and above, gobo'd on 1/64th. Yellow balloon with yellow dyed water. Retouching / correction in Aperture. Colours as shot, not artificially added.