How about make your own molds: http://www.culinart.net/silicone.html
Try either the Silicone Plastique or the Silicone Spread Food Grade, both are non-toxic and safe for use with food.
I saw this, also. But how much does that stuff weigh? If you need more than a few pounds, it's going to get kind of pricey.
Even those cookie cutter molds are expensive. I think I figured it to be $60 for an Alpha, Sigma and Tau. And for a Gamma, Phi and Beta, it would be more than $70!
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