I use scaling all the time with a combination of normal scaling and the SP4 scales. This works pretty well in PP2010 and is decent enough variation for me. And with the autoscaling clothing works without problem as well. This gives me heights from 160-190cm, which covers most adult people.

If you use the yscaling it will not bend properly in the more extreme poses, so I tend to avoid that, although in many cases it can be used without problems.

Anyway - no need for merchants to achieve this