Well, that's not what he wants. He doesn't want to release his current familiar, probably because the character has a bond with it, not just a magical bond but an emotional bond as well. Which is why I would say, take the Improved Familiar feat, spend the 100gp, and submit the character to the judges for a level up and I'll definitely approve it. I far prefer that method over killing/releasing your current familiar and grabbing a new one.
Basically, I don't think a new rule needs to be proposed, nor do I think the SRD feat needs to be changed.
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