Can't say I have any experience combining any of those things in one season, but I can see how it might be fun.
Really there's two schools of thought I have on this:
First, that a roto-league is much more of a long-haul challenge, with much less luck involved and a more "serious" setup.
Second, that a H2H league is more condusive to rivalries, trash-talking, crazy-happenings, and gets more people emotionally involved in the league.
I honestly don't know which one I prefer yet, as I don't do noticably better in either one and my personality fluxuates between the two extremes seemingly every week.
I can say that I like the idea of a playoff system in a roto-league, to keep the guys in the middle of the pack involved until the end, but in the same token I'd hate to see somebody lead by a ton through the entire season just to get fluked-out in the playoffs by something as stupid as a rainout or the other guy having fifteen double-headers.
It's tough finding the proper balance of regular season vs. playoffs to keep both of them legitimately worthwhile. Good luck.