Zeus also made a freewheel with aluminum cogs. IMO it was one of the best freewheel designs ever: all the cogs used the same spline pattern and were fully interchangeable, except the final (smallest) which was threaded and held the rest in place. The cogs were machined so that no spacers were needed, either. The body was designed to use either the ubiquitous 2-prong Regina tool, or Zeus' own splined tool (later copied by Regina and Atom, among others).

Of course, they've been out of production for almost 20 years now, but they do turn up on eBay pretty regularly and seem to sell for about the same as the SunTour or Regina aluminum cog units, and usually much less than a Campagnolo unit.