I have a hand-held veneer stitcher from Vacuum Pressing Systems. Not sure of the manufacturer, but I think they all are similar.I got it for a specific job involving a house full of veneered cabinets. It is much more productive than hand taping, and no doubt slower than a stationary stitcher. It works well with flat veneers. The joint is not quite as strong as a taped joint, so not as successful on buckled material and requires a little more careful handling of stitched leaves.
Stitching is a bit problematic in that the thread thickness makes an impression in the veneer.I have buried the sttiches in the glueline on door backs to avoid the labor of removing them after pressing, but am not totally comfortable with doing that on faces for fear of telegraphing. After removing the stitches on faces, I have steamed up the impressions to reduce the required depth of sanding.
The best jointing system for veneer leaves is probably a glue splicer, although I never have used one and they may not be as simple to operate as I would like to think. They give you a glued joint and get rid of the labor of removing tape or stitching and the risk of residue ghosting around the joint .