The easiest way to adjust the joints in this situation is to use the scale dials.

The best results for what you are trying to do would be obtained by using D|S's figure mixer because it operates on the rigging information in the required way.

The only alternatives are adjusting by hand calculating/editing or a script (none known to exist).

However you get a modified skeleton, you should expect to need to do a lot of tweaking (especially of tricky areas like hands and fingers).