To Have a Tail or Not is the Question?

SOC raised a good note in the JSF potentail buyer about the advantages of not having a tail and giving the example of the tailless X-31, which proved more manuaverable without a tail than with one. The USAF and NASA have done research in tailless aircraft with the X-31 and the X-35, and both aircraft proven that tails are not required (ex. of fully operational B-2s). Other advantages of tailless aircraft is that they have a smaller radar cross signal. That is probably why Northrop and McDonnell Douglass decided to make the YF-23A with a ruddervators (combined rudders and elevators) for the ATF program. And one of the orignal three competitors for the JSF program had a similar design to the YF-23A but with one engine.
Even though the tailless concept has been proven to make a aircraft more manuaverable, produce less drag, and give it a smaller RCS. But the one of the reasons I figure why the F-22 and the 2 present competitors for the JSF contract are not tailless is because tailless aricraft are too unconvertional. And with so much money in the balance no one really can risk billions of dollars in something so unconvertional nowadays.