How about I speak for TRU? I run one of their stores.
First of all, GBA did
release early at TRU. We sold it a week before the original release date and 3 days before the "revised" release date. Nintendo supported a "sell it as soon as you get it" campaign with GBA.
I wouldn't be surprised at all if we have a "soft release" for Gamecube. In fact, if you read my past posts I've been stating this for quite some time. The fact that there is no real reservation program makes it very easy for Nintendo to allow retailers to sell it as soon as they get it. Has their been any official indication of an early release? No. But I still think it a very strong possibility.
BTW, it's very common for games and consoles to arrive at retailers well before launch date. In fact, my store already has 2 Xbox games in stock (Fusion Frenzy & ...I forget the other one). GCN games appear to begin hitting within a week or so. PS2 consoles showed up at my store about 2 weeks before launch, Dreamcast came in about 1 week prior to launch. It's no big deal.
One thing is for certain in the retail world: you can count on Circuit City to launch at least one day after
release date. They just can't seem to get things together over there.