Manual Herb Harvester for Greenhouse-Grown Fresh Herbs

We have a hydroponic lettuce and herb operation in NSW, Australia. We grow a range of herbs for our mesclun mix. My dilemma is, now that our business has grown we need a quicker way to harvest the herbs, other than with scissors. Our herbs are grown on tables about 1-1.5m above ground. I was hoping to find a device to harvest them and wondered if you knew of such a thing, or of anyone who might be able to help. It would have to be able to be held over the crop by one or two people.
We grow cress, mizuna, green elk, cutting celery, and salad burnet. The most time consuming one to cut is the celery.
One of the reasons our business is successful is the quality control that comes with such labour intensive attention.

My primary experience is with field crops, not commercial greenhouses. I can imagine several prototype devices I might suggest, but would need serious R&D. I think there are devices that can clip onto a set of runners, and work like a side-bar cutter. In "chain-saw land" they were called Alaskan Mills.
There are two very serious Greenhouse magazines, with solid technology for support. The one in British Columbia, Canada has got quite a circulation. Their annual conference was just in October. That would have been the place to go to find prototypes or inventors for your situation.
greenhouse.hortport.com/Current_Issue.htm
The other is in Salem, Oregon, known as Growing Edge Magazine
www.growingedge.com/magazine/back_issues/view_article.php3?AID=90620
I wished I could help more, but this is not my real background. I will be in Brisbane in September, 2007 for the Nexus Conference. If time permits, I would enjoy seeing what you came up for improved flow of harvests. An Alaskan Mill kind of arrangement would be where I would start. How else can I help you?