The secret launch makes absolutely no sense.
If they were delaying specifically to give you the latest and greatest, they'd be telling anyone who'd listen and they'd have it on the configuration page - the x1950 justifies a longer wait for those holding out, makes Apple look good, generates sales from people who don't want the x1900 anymore, etc..
It's entirely possible that you'll get an X1950, but if it happens, Apple wasn't planning anything - they just can't find their arse with their hands.
If they were delaying specifically to give you the latest and greatest, they'd be telling anyone who'd listen and they'd have it on the configuration page - the x1950 justifies a longer wait for those holding out, makes Apple look good, generates sales from people who don't want the x1900 anymore, etc..
It's entirely possible that you'll get an X1950, but if it happens, Apple wasn't planning anything - they just can't find their arse with their hands.