It's certainly natural for CGN to raise the price in response to demand, but they made their move prior to the street date (probably anticipating demand based on wishlist popularity of the variant, but still...) as I noted here last week:
http://community.comicbookresources....00#post1132500
I did manage to snag the Kirby cover from IST yesterday but had no idea it would be gone almost instantaneously. No speculative eBay plans for mine - it's got a home on my bookshelf for years to come.