Is there a coupon plug in that you have tested with? Glimlag? AwoCoupon?

Theoretically all coupon components/plugins should work just within our templates.

Because creating coupons, grouping, setting expiration dates etc.. are backend related things. (where our templates are not effective).

So, as long as the 3rd party component be able generate valid coupon codes for Virtuemart Component. Everything should work out fine within our templates in the frontend as well.