i've been looking at adapters too...
check out Adaptitusa.com, they have conversion adapters for any lug pattern. you'll find a 114.3mm (4.5 in) to a 112.
here's a link
the only think you'll have to take into consideration the Center Bore (C.B.) and the differences in offset. I'm looking to do the same thing but don't have all my ?'s answered yet.