Blue Moon 28s does a fairly complete range-because of the integral bases these tend to be just a tad taller than the Brigade Games musketeers:
You can knock a mm or 2 off the thickness of the base w/ a file or sander.
Also, Warbases has a fairly complete rage of 28mm figures for the period based on the TV series rather than the various movies:
link
The TV musketeers tended heavily toward individual costumes with lots and lots of leather bits and pieces rather than the classic tabards. Even if you prefer the movie look for your musketeers, however, the Warbases figures could provide you with misc. henchmen, guards and various civilians.
Jon has already mentioned the Brigade games figures, which are very nice.
Also, Black Hat Miniatures, I believe, used to have a range of 25-28mm musketeers, but Back Hat sold off most of its miniature figure ranges and I don't know where these are now. The Black Hat figures aren't nearly as nice as the other ranges, but they did have a couple of henchmen with clubs which are useful.
The Brigade Games, Blue Moon, Black Hat and Warbases (I believe as I don't have any yet) are all, IMHO, roughly compatible with minor work (Blue Moon bases are a bit thick but that can be worked with).
The Redoubt sculpts are great, albeit, IMHO, can vary quite a bit depending on the quality of the molds. In any event, as Jon says, the Redoubt minis tower above the others.
