I haven't seen these in stores yet but it seems that Mega Bloks has started making Skylanders Giants sets.
Toysrus.com has about 8 different sets up right now and they've been adding them at a new set or two a couple of times a week.
Prices seem to range from $8.99 for a basic figure kit to $120 for the Castle set.
If my son sees these I'm sunk
Anyone else interested?