I love the slow time shout. It's epic to be able to slow down time, jump out from cover and shoot your enemy before he can even react. But I hate that I have to wait for the cooldown before I can use it again. I think it would be cool if there was a spell that could slow down time. Even better would be if it could be switched on and of like the Khajiit night eye racial(I think).
I know Midas Magic allready has a Fus Roh Dah spell so it shouldn't be to hard to make. So if someone with modding experience and a little spare time could make one I'd love it.

This isn't exactly what you're asking for, but it does let you convert mana to shout cool down.
http://www.skyrimnexus.com/downloads/file.php?id=2318

That looks cool actually. It's not what I was looking for but I'll try that one too.