Associated Press reports:
A federal law? Which of the enumerated powers does this come under? None, in my opinion. Leave this to the states. That is where person-on-person criminal laws belong.
Lawmakers outraged over Casey Anthony's acquittal have responded by proposing so-called Caylee's laws that would allow prosecutors to bring felony charges against parents who do not quickly report missing children.* * *"Casey Anthony broke new ground in brazenness," said Florida state Rep. Scott Plakon, who is sponsoring the proposal in his state. "It's very sad that we even need a law like this, but Casey Anthony just proved that we do as unfortunate as that is."* * *Other states are considering similar measures and the online petition at Change.org, started by an Oklahoma woman, calls for a federal law.
A federal law? Which of the enumerated powers does this come under? None, in my opinion. Leave this to the states. That is where person-on-person criminal laws belong.

What would be better than "Caylee's Law"? An enforcement of ethical rules against defense teams and allowing prosecutors, when there is no evidence of some alternative explanation (e.g., Caylee drowned in the pool) proferred by the defense, to forcefully make that point. Casey Anthony's lead defense attorney ought, at a minimum, be suspended for his scurrilous attacks on Mr. Kronk (the guy who found the body) and his attacks on Mr. Anthony (again, completely without evidence). Moreover, defense counsel should not be allowed to argue these alternative explanations without evidence.
I'm not inclined to restrict what the defense can argue. It would be better, in my view, to recognize that Justice Stewart was right in his dissent in Griffin v. California regarding comment on the defendant's failure to testify:
The weight of scholarly opinion had a much larger proportion of persons of sense in those days.
Understood that there are some limitations to what you can do, but the idea that a defense attorney, without evidence, can accuse people of crimes as was done here, is a problem. The treatment of Mr. Kronk was outrageous.
I wholeheartedly agree with you on getting rid of the idea that the prosecution cannot comment on the accused's silence. That would likely solve a lot of the problems that I just pointed out.