Ford won't risk upping the price of the mustang; its their flagship car and has been outselling all other sports cars for at least a decade.
Expect the 05 v6 and entry level GTs to be priced around the same, but you can expect another 'special edition' car to be released with the 41st Anniversary cars. I see a Boss 281 coming up...
The 06 Cobra will probably be priced a lot closer to 40k with the 5.4 DOHC blower and all.
Maybe I should just stick with a 98.