Looks like one retailer MAY have the jump on everyone else. RCHeliGears is taking pre orders and has listed their retail pricing. Looks like they are stocking all three models for sale on Jan 8, 2010.
$333.00 T-Rex 500, $360.00 T-Rex 600 and $416.00 T-Rex 700
Esprit Models is now taking pre-orders as well with a $100.00 deposit, however no pricing has been announced by them.