Sorry, but I doubt that is possible for you to do. A woodworking shop would be able to do this, but it would require jointing and possibly doweling the two edges, and then gluing the two pieces together using many large wood clamps. In addition, after this was done, you would probably still be able to feel and notice the seam because there are probably small deviations in flatness of the two pieces that will prevent the seam from being dead flat everywhere. The only way to deal with that would be to sand the whole surface and then refinish the top. In addition, because of the need to remove a small amount of wood in the jointing process, you might have a bit of difficulty lining up the attachment points of the table top to the frame.

Because of this, it would probably be just as cheap to have the shop build a top from scratch instead of trying to finesse this. I know that's not the answer you want, but I just don't see an easy way to do this which is within the capability of the average person who doesn't have access to serious woodworking tools and the skill to pull this off. I've been doing woodworking for over 50 years and, although I could do this job, I would question whether the effort was worth it.

Thanks for your input, Kudzu9! We'll keep this in mind. We haven't had much luck getting responses back from woodworking shops.