Mixing Invocations and Spells

[expirement10K14]

So, looking at the Ultimate Necromancer at liquid material wiki, I got an idea. What if there was a class that used both conventional wizard/sorcerer spell casting as well as invocations. Both would progress at slower levels, but they would add versatility to the caster by allowing low level spells to be cast at-will. I am not very good at home brewing, but what kind of tips do people have for the idea?

[Swooper]

You mean like Eldritch Theurge?

[expirement10K14]

You mean like Eldritch Theurge?

Yes, but as a base class, as I thought that it would be interesting to play. In order to stop PrC abuse I was thinking it would be best not to call them invocations.