Stick some blocks onto the bottom? Not the most elegant fix, but it would work. Couldn't get it as tall as you want for other stuff, though, so I'd tend to think the monopod brace would be best. Are you planning on laying down when using this? I'm afraid I can't really see using either from a crouching or sitting position, but if you're prone, that brace just could be the ticket.
Oh, and as a side-note, how heavy is your lens? That monopod you linked apparently only holds 1kg.




