300B as a tube for a Class A/B Amp. or why not?

I have looked all over the internet to see if anyone is making a Class A/B amp using the 300B. All I could find was single ended class A and Push/Pull Bios as class A. In the push pull Class A configuration the amp can make about 25 Watts. But the plate dissipation is 40 watts a tube so as a class A/B it would make considerably more watts, as well as run cooler and the tubes would last longer.
Does anyone know of a good reason that it should not be used in a Class A/B amp? I did notice that the curves are terrible at very low amperage, the worst I have ever seen, could this be the reason?

Cool ideal but cost would be my major concern.   How much is a 300B running these days?

You can get a single 300B (new production) for between $90-100US. The NOS prices are astronomical, though, from what I've seen.

Parts express has a matched quad of Electro-harmonix 300B $371.37 with free shipping. I would think that a Class A/B amp would be able to produce 50 watts of power.