Lancer Miniatures have just started to produce a 10mm SYW range. Currently on offer are Prussian musketeers, which can be bought in groups of four figures, or a regimental pack of 30+ figures. Interestingly this pack has two standard bearers so that the much loved two flag unit can be produced without the need to convert figures (as has to be done with the Old Glory range). There are also Prussian cuirassiers currently available.
The gamers of thirty to forty years ago have a lot to answer for as a result of their relentless, search for realism. Damnitz has the right idea - if you crave that type of realism then become a re-enactor. Personally I prefer the warm and dry of the wargames room and a free-flowing game.