A Loophole in Contribution Law?

The New York Times reports today:

Mrs. Clinton has raised nearly $50 million and spent about $35 million; both the
infrastructure she has built and whatever money is left at the end can be
transferred into a presidential race if she decides to run.

This raises an interesting possibility. Imagine that a presidential candidate wants to allow people to contribute more to her campaign than is currently allowed under Federal campaign law. She could sign up to run in the off year election for the House and the Senate (and maybe have her relatives run for House and Senate in the same state). Supporters of the presidential campaign make maximum contributions to the House and Senate campaigns. To be extreme, imagine that these are sham candidacies and that she and her relatives spend almost none of the money contributed so as to maximize the amount that can be transfered post defeat to the real presidential campaign. The supporters who maxed out in making contributions to the sham campaigns can also max out in giving to the presidential campaign. And voila you have neat/scary way to end run the contribution limits.

Should we require candidates to give back excess funds to their donors? Or should we at least require some kind of attribution rule so that contributors can't effectively double dip? As it stands 30 cents of every dollar give to the Clinton Senate race is likely to support the Clinton presidential race.