It's worth noting that 140, 150mm stems aren't absurd. Modern track bars like the Scatto are at least 20mm shorter than normal handlebars. So, if you are used to running a 120mm stem on your road bike, switching to Scattos (at 20mm shorter) will call for a 20mm longer stem.
I remember going into bike shops asking for 140mm stems and the staff looking at me like I don't know what I'm talking about.