Ron, there are a jillion places out there where it "could" be done. If you supplied some info on where you were, that might help a little. One way to start would be from a search at www.switchboard.com for something like "custom porch posts". I would guess that you would have a lot more choices in some place like North Carolina or Michigan than in Kansas or New Mexico, but we can't give you any idea how to limit your search without some idea where you are.
One thing that you might want to consider is structural foam posts. Check www.style-mark.com as one example. They were featured on one of the home improvement TV shows, and there are other manufacturers of these around too. No bugs, no rot, etc. is awful enticing and the quality of a well designed part can be pretty impressive.