This filament guide requires a bearing, but allows the spool to be strung anywhere around the printer and makes for some smooth filament action.
It may at first be a little tight on rotating to follow where the print-head goes, but it'll get there over time.
Putting it together can be rather difficult. To insert the bearing in, I actually used vice-grips to put enough pressure on the bottom and top to fit it in. You can be creative though.
I don't take any responsibility for injury's trying to get this thing to work.