Pre-historic Europeans in America?

I read the Madoc thread here recently and so I thought it was interesting when I noticed this bit in a Cracked article:

Spoiler Alert, click show to read: 

In fact, the whole assumption that the settlement of America was done by a single cultural group from Siberia is more or less based on the distinctive pointed Clovis tools found in a New Mexico town called Clovis (archaeologists are not particularly inventive when it comes to naming things). The strange thing is that researchers have found no link between the tools of ancient Siberians and the Clovis people. In fact, the oldest Clovis tools have been found on the East Coast of the USA, not the west, as would be expected from people who came in from Siberia.

However, the tools share surprising similarities to those made by a group called Solutreans, a European tribe who used to live in Spain and southern France. According to Dennis Stanford of the Smithsonian Institute, Solutreans might have been able to reach the Americas by paddling along the coasts of Atlantic ice sheets 22,000 years ago, and thus got a massive head start in the settlement of the continents. We're actually kind of enjoying this theory, if only because it would bring a deliciously M. Night Shyamalanian twist to the Spanish conquest of the Inca empire: They were raiding their own people all along.

I find all this stuff about ancient migrations very interesting, so I was wondering what the residents here thought about this sort of thing.

Here's a Washington Post article with some detail.

Is it credible? Fringe? Probable?

Vague recollections:

*Signs of human settlement in Central America as far back as 40,000 years ago

*Native American skulls of 10,000-15,000 years ago present wide variance, while those from 2000 years ago are much more homogeneous

*So, migrants might have come from multifarious groups in Northeast and Southeast Asia, Oceania, and Europe, continually or in waves from 40K to 10K years ago; somehow, one grouping destroyed or assimilated the rest by around 2,000 years ago

Can't say where all that comes from...

I think it's possible, but the Washington Post article states there's not a lot of evidence to support the hypothesis. Just because the stone tools resemble ones made by a European culture doesn't mean that they where necessarily made by that culture, designs and styles can be invented by two separate cultures independently of each other.

Check out this Ancestral Peublo mug, for example. It looks almost identical to a modern-day coffee mug, but it was made around 1200 AD, centuries before European contact.

Since the continents have been locked together, not that weird. In Russia they have buffeloos

Kennewick Man was clearly not Asian, or Indian and caused a controversy. More ignored than investigated.

Eastern and Southeastern tribes have a legend of a white people living in Kentucky, whom they eventually wiped out. No tribes lived there, they said because of ghosts, but used it as a hunting ground. That was during early European contact. I have no idea what the archaeological records of Kentucky contain.

Wikipedia seems to indicate that Kennewick man is most likely Polynesian/Ainu.