Does anyone know........Will adding meringue powder to a non crusting buttercream help it crust? and, if so, appx how much to add to 1 batch?
Thanks!

Depends on the recipe, but it should help. I'd start by adding a tablespoon.

Here are some crusting recipes as a comparison to your's:

http://www.cakecentral.com/modules.php?name=Recipes&sort=recipename&sort_dir=ASC&op=search&chname=X&chingredients=X&searchtext=crusting&cat_id=47&x=29&y=7

Also, here's a thread on meringue powder:

http://www.cakecentral.com/cake-decorating-ftopicp-4610.html

HTH