Have you looked at Feisol? You might want to consider a CM-1401 carbon fiber mono - super light, sturdy, secure twist locks and a decent monopod bag, and priced like aluminum. I ordered through feisol.net with no problems at all.
I use either a ball head (Feisol CB-30C, not recommended because you have to crank down the locks so hard it hurts your fingers and even then it can only handle very light loads) or a Manfrotto 3229 swivel tilt head with quick release. The CB-30C/3229 combination handles a 300 f/2.8L / 40D / grip with ease.
I don't know if this is a problem with other monopods, but the Feisol seems immune to dust somehow ... even at a baseball field when all of my other equipment seems to finish the day caked with tiny bits of the infield, the mono says clean.