well there is no huge f/2.8 superzoom, which sounds like what you want. The one you linked to is the best for what you said you were looking for, *except* for the speed issue. I would consider getting the lens you linked and adding the 50mm f/1.8 to it for the specific purpose of low-light and fast aperture use, its only some $90, great quality, fastest aperture you'll get under $350...

As far as combining the need for huge range and fast aperture, sorry but you get one or the other.