FLM makes a ballhead which will not tilt sideways if an additional clamp is locked. Once tripod and camera are level and this clamp has been fixed adjusting the camera becomes more like working with a two-way pan-tilt head. All in all it is a nice head which replaced my Linhof Pro III.

Here is a description/praise of this head (Workshop- 2 -> "An exceptional ballhead"): http://www.poelking.de/index_e.htm

best

Stefan