staff users unite!

[kme]

Oh ya, ring of wizardry type I, doubles your 1st level spells per day, 20,000 gp. Similar rings for other spell levels. There's also an epic feat to give you an extra ring slot if need be. Just saying...

Yeah, use the ring of wizardry III. It's not like they are expensive at level 21.

Guidelines for crafting custom staffs exist. Without them, craft staff feat would be pretty bad since default staffs are not that good. See with your DM if he will allow it, but he may want to limit the number of spells the staff holds as it would be abusable with your ability.