I believe schwing made one slewed on 3rd stage

Elliott Equipment made a "versa placer" made just like you described. bout 85' of boom the telescoped straight in and out, the tip section rotated left and right, really slick unit, i think had a putz 70 pump kit in it. for whatever reason they quit making it around 2004 i think. you could even get it with a winch on the boom to use as a small crane, or a man basket for it. we had several around this area a few years ago, but they have since been sold. if you were doing interior floors with the roof on it was great.

Cifa had one that could do that also.