LostGraduation
CAGiversary!
Not sure if anyone but me was hunting for this, but Ubisoft has it as a digital DL for 29.95. Use the promo code "10thanks" at checkout for another 3.00 off. Not tax, so I think this is by far the cheapest this is available atm.
http://digitalstore.ubi.com/180/9058/product/Buy-Dawn-of-Discovery:-Gold-Edition-Download
http://digitalstore.ubi.com/180/9058/product/Buy-Dawn-of-Discovery:-Gold-Edition-Download