Amazon seems to have the Combiner Wars G2 Superion Giftset Transformers Generations Combiner Wars Superion Collection Pack in stock and it’s shipping now! He shouldn’t be far behind elsewhere now as well. Head on over, he’s listed for $99.99 USD with free Prime shipping for those with it.
Update – after a bit of in and out of stock over night, the listing page seems to be removed. Check via this link to see search results in case he pops back under a different item number.