I got the non-IS f2.8, having faced a similar dilemma. The f2.8 makes a huge difference to my video work, which is a big part of what I do.
I'm not a huge fan of IS, mainly because I tend to have the camera supported anyway, and because I feel that when you get to the slower shutters where IS would help, the combination of subject motion blur and focal length are going to be bigger problems that IS simply cannot solve.
I have a regular manfrotto monopod (the 680d I think, the short one) and a manfrotto video monopod (I got the version with the ball foot, but without the video head) and this works very well.
I would be exceptionally surprised if you cannot get sharp images at 200mm (even x1.6) on a monopod with 1/125th. That would suggest a technique problem or the wrong focus mode / pattern.