I am actually working on a blog article looking at this. A friend spent the big bucks on an orbital shaker table some time ago. I have a stir plate. Planning to pressure cook wort and the stir plate, shaker table and shake method and do some viability and counting, fermentation with split batch wort. I may try to weave in a dry v rehydrated version as well... but with very rough manufacturer cell estimates in dry yeast, not sure it would be valid.
In the "Selecting Yeast Based on Strain.... yada longest seminar name ever" Kevin Lane said their pitching rates were based on biomass (dry weight) and not cell counts, advice that follows closely with Mark's recommendations. They are also adjusting their viability recommendations quite a bit. I was pretty surprised frankly... it's a large shift from the White Labs and Wyeast advice, but it was also seemed to be inferred that WL was propagating to mass in their new process and that the cell counts were significantly increased in their new process/packaging.
I was surprised in Kevin's advice on pitching dry and not rehydrated, but apparently they don't see in their labs the significant yeast die off from pitching into wort that others have reported. I "seem" to get better results with rehydration, but willing to admit personal bias. I spoke with him briefly after - he said the difference was really in lag times and not in ester/phenol expression. It was a bit boggling as I have done side by side tests with meads (1.100 gravity must) and the results were very different between 71B-1122 dry pitch and rehydration with GoFerm (as recommended by Schramm and Pietz), with the sugar break feedings.