Hehehe... Picture on the left isn't mine it's one of the mods that works for this....

Macromancy 3
http://www.nexusmods.com/skyrim/mods/71932/?
lets you steal potential size from beings or convert dragon souls into it.... Raising your maximum size, while adding lots of stuff to change your size.

The two on the right are me messing around with spells from Phenderix's Magic Evolved. The one has me rather large easly to see.... the other down in the corner... well that little speck with the potion bottles? that's me.... I can get smaller but If i get much smaller I couldn't get around (would be moving to slowly.... eventually wouldn't be able to move at all and wouldn't be able to see me)

But size dose affect speed as little legs VS big legs ... well.... it takes into acount that.

Just thought I would share though


Also Interestingly enough people look up/down at you.