Its feasible that a Neanderthal offshoot could have made it to the Americas much earlier than modern humans. If their numbers were small enough and they ended up dying out long ago there wouldn't be much evidence left.
Out of Africa theory is becoming full of more and more holes. This is all speculation, so take it with a grain of salt, but I think it should now be called in and out of Africa, because it appears humans to have came out in waves, where our most distant ancestors left long before the emergence of modern humans. These ancestor offshoots evolved in the middle east and more northern lands, some went even further, perhaps over the land bridge to the Americas, never to return, while others stayed closer to the African land routes and interbred with late comers. Perhaps some of these early waves of hybrids even migrated back to the African boarder regions and interbred with an emerging race of more modern humans, before they eventually left Africa for good, and re-interbred with with their distant relations who had been evolving out of Africa for a few hundred thousand of years.
In the new theory there is still the assumption that we originally evolved from the African Great Apes, though there is no direct out of Africa linage, because many of our hybrid ancestors had evolved outside of Africa for hundreds of thousands of years. Early waves of evolving hominids bred with the later waves, in a none linear pattern, with migrations going back and forth, to and from Africa, which eventually lead to the emergence of what we know of as modern humans.
