Photomerge is wonderful, however you must drop down to 8 bit for it to work, which is not good - perhaps PS 9 will support this in 16 bit like it should. In the meantime, if you will do the reverse-shift technique with your TS-E lens (if you have an L bracket), then you can keep your file in 16 bit and align the images manually and just erase away the seam - if done correctly, it only takes a minute or two and the results are great, and you've got a 16 bit file...
Tim Ernst in Arkansas
http://www.Cloudland.net