So you want to combine the two by ripping out the middle? I would get a contractor for that (unless u can do it), make sure the header going across isn't a load bearer. closet companies aren't cheap (I just had someone do ours,,,cabs only, no construction). It all depends how fancy you want to get. After you get the space cleared out and combined, you could do it yourself for cheap w/the white wire rods and shelves. Or call one of the companies and spend 5-10K. all depends on what you want.

I would check out Pax from Ikea their storage is awesome and totally customizable and a fraction of the cost of a closet company. There is a company called easyclosets that walks you through the design process