First of all, mana abilities don't use the stack. Second of all, I hope you don't mean an actual queue. A stack and a queue are polar opposites. I noticed that on your version of Stifle, you refer to stack abilities. Are you just trying to make mana abilities more confusing? Because putting them in a queue doesn't add any functionality (since queue abilities can't interact) and in fact makes them useless in a lot of cases (you can't activate them during the resolution of spells or abilities, for example). There's a good reason that mana abilities happen instantaneously. Putting them on anything is a bad idea.