The web site, since "fixed," when one looked at the feature comparison tab, showed the 8GB model in both iPhone 3GS and iPhone 3G versions (as above). Now, to me, that seems more like an "oops;" someone put the check in both columns.
That seems confirmed by a message sent by Rogers to Gizmodo,
You're right, there is no 8GB 3G s iPhone. There is a formatting error on our website. It is being corrected asapIn fact, the formatting has already been fixed; that extra checkbox no longer appears. That doesn't mean that an 8GB iPhone 3GS isn't coming; it's just not coming yet.