awesome are not monolithic slates or work-spaces that could be "scrolled to". In general you have to re-think what you are looking at. Tags are not separately rendered spaces, they are lists of windows. This is part of the flexibility of awesome and allows you to do things other window managers cannot, such as pull up more than one tag at once - rendering them in whatever layout the first called tag is defined with.
The other tags besides the one you are looking at are not being rendered in another space, they are not being shown by X at all. When a different tag is called the current windows are hidden and the other tagged windows drawn.
You can see the effects of this if you have a poorly programmed application that re-renders itself on being re-shown even if it the same size. These apps will take a noticeable amount of time to pull up when you switch tag views.
While it might be technically possible to re-write everything with OpenGL or some other buffered system so you could pre-render things before showing them and thus show transition effects, this isn't the focus of the
awesome project and I don't expect to see a feature like that soon. Enjoy it for what it is.