The New York Times has posted the latest data on contributions to Presidential campaigns here. Among other ways of slicing up this information, you can click on a candidate's name and see a map showing the size of contributions from different cities/states that each has received through the third quarter.
For almost all the candidates, the giving is quite lumpy. The east and west coasts give more money (not surprising, as more wealth is there), and particular candidates have giving hotspots. Romney has raised a ton of money in Utah (more than he has raised in Massachusetts), Thompson has raised more than a quarter of his funds from people in Tennesee, Obama is strong in Illinois, etc.
The notable exception to this lumpiness is (drum roll, please) Ron Paul. His campaign contributions are spread out quite evenly (he's done better in Texas than elsewhere, which is not surprising, but his Texas total is only three times his haul from the state of Washington and a bit smaller than funds from California). And his receipts come from all over. Indeed, and perhaps unsurprisingly, he does better in smaller states, which may have a higher percentag of people who lean libertarian. He has received more money from North Dakota, for example, than either Romney or Giuliani. You can decide for yourself whether this means we should consider him to be the only candidate with a true 50-state appeal, or the candidate for people in sparsely populated and over-represented (in the Senate) states.