Yup. In theory, anything is up for grabs. We just haven't seen anything worthwhile from a 3rd party. (Haven't seen much worth while from WotC.)Jeph said:We use only WotC stuff not because we don't allow other things, but merely as other stuff just hasn't really stricken our fancy enough to make us want to try it out, for the most partish kinda sorta.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.