Sure I do. Instaid of using units for the novas, make an ability based off of, lets say Breath of Frost

. Just set the initial damage of the novas to the normal damage of the Breath of Frost, then there is a Damamge per second field, change that to the Dmg. Per Scnd, and make sure you set an appropriate duration, and make a new buff based off the breath of frost one, but make the target art the art for breath of fire, in the abilities section. Now, instaid of making units move, just make units, and have them cast like so:
For each integer A 1-36
Create 1 MOFO at target point of abil being cast
Order Last created unit to breath of frost position of target point of abil being cast offset by 250 towards (Real Variable)
Add a 3 second Expiration timer to last created unit
Set (Real Variable) = (Real Variable) + 10
There you go. It will now hit sleepin creeps, AND do damage per second with a flame effect.
EDIT: Also, when you make it so a spell is cast, instaid of a moving unit, the spell will go out of bounds, instaid of just stopping there and not moving (units cannot go out of bounds, unless you move them instantly with triggers) making it look more realistic.