JOEL - You are pretty much correct. Not much conclusive evidence has been found yet on this continent(although some has been found in Arabia), and it is possible that no one is looking in the right place. We are not even sure where the right place is to look.
The Bible has a big head start in terms of the search for archaeological support. Scientists all over the world have been searching for many centuries for evidence that supports the Bible, whereas it has only been about 170 years since the coming of the Book of Mormon, and actually not many people have really been specifically searching for Book of Mormon related evidence. Perhaps, like the Bible, as more time passes more will be found. Please see my page on archaeology and the Book of Mormon at:
http://www.mormonhaven.com/scriptur.htm#27

The Smithsonian is not quite as supportive as you think they are concerning everything that happened in the Bible.
For example, they have issued a statement doubting the authenticity of the Genesis account of the flood, where they say:

"thus far, after literally hundreds of archeological excavations at different times in the Near East, no all-encompassing flood stratum has ever been found."

See:
http://www.answersingenesis.org/us/newsletters/0403lead.asp

and

http://www.mormonhaven.com/naval.htm

Also it has been calculated that an ark of the size specified in the Bible would not be large enough to carry a cargo of animals and food sufficient to repopulate the earth, especially if animals that are now extinct were required to be aboard also.
So did the flood and Noah's ark really happen, even though so far they have been scientifically shown to be nothing more than folk tales? If we believe the Bible to be perfect and correct in every way, we cannot rely on science to provide evidence for it; we must rely on our faith to believe that it happened the way it said it did.
So it is with the Book of Mormon.