Hehe I think somebody's getting mixed up. There is a level 50 rules pack which includes rulse on how HP, spells, saving throws etc. all advance up to level 50. This is just a simple case of editing the default 2da files.
The XP cap file that u can dowload is called XPCap.2da, It sets the XP caps to -1 for all classes which means u can go as high as u like. If u edit this file u can set your own XP caps for each class. ToB, from what I've read will have XP caps of 8000000 which allows mages up to something like level 35 IIRC etc. I don't know about what spells will be available
. But by editing the MXSPLBRD.2da and MXSPLWIZ.2da etc. files u can set whatever amount of spells u want your character to be able to memorise at each level, up to the practical maximum of 12 per level of spell per day.