I have read in numerous sources that after 9/11, all US commerical fights were grounded,

Yes that's true.

 however, the US Govt had planes go around the US, pick up certain Saudi families and bin Laden family members,

This is true as well but I don't think I've seen a list of who exactly they picked up. I do believe they did get certain people out of the country, some of them bin Laden's on your tax dollars. The date's are fuzzy on this as well. The bin Laden's did own several pieces of property here in Massachussetts (Boston, Charlestown, and Sudbury I believe) if I remember correctly I don't think there was family at all of these locations but something I think did go down with FBI and or Secret Service in the Charlestown or Boston locations.  

take them to a central US location and then fly them out of the country before the FBI could completely interview them.

I don't think I've ever seen it disclosed as to where they were taken or if it was a central location they all went to. If I remember correctly there was a bit of an uproar about the fact that they were not interviewed before we got them out of the country.

My questions are, how come this has not received more attention,

I think it did not get more attention because it was done quickly and quietly during one of the most overwhelming and devastating events to have occured on US soil. I think the news folks were spread a bit thin and the only place you'd get this sort of story would be an independent source. The big news outlets were still showing the planes crashing into buildings. So, they'd have to go back to look into it now and I think it's not something you'll see covered by mainstream media until some later anniversary of 9/11 or by some documentary filmmaker. At which point most people will probably dismiss it as "conspiracy theory" nonsense. Basically they dropped the ball.

does everyone out there even believe this account or even have heard of this before,

Yes and yes on my part anyway.

and what is everyone's opinions about such claims?

My opinion is most people will not consider it and could care less. It would probably be difficult to discover what the hell they were doing exactly and more than likely the information is classified.

Also, can anyone offer rationales for such a thing to have happened?

Well, it's well documented that the Bush family is very tight with some of these Saudi families and so is Big Oil. I think the original reason given was that it was done for the protection of these people and that they were thought to be innocent. I'll try to look back to see if I can find something about it but I'm pretty sure they took some of these people out of the Boston area...then later claimed they were never here. Kent probably has info on this stuff and I think he even brought it up here before.