Recently I have been added occassional dry yeasts into my brew cycles.
I find rehydrating the dry similar insurance to stepping up the liquids. White Labs states you can pitch its tube into 5 gallons and you are supposed to be good to go. I find stepping it up a couple of times isn't that much of an effort (now that I have a fairly equiped fermentation area, with stir plate, PBW, Iodophor, Star San, etc.).
The first time I used Nottingham yeast was for a Big brew recipe many years ago (Rob Moline's recipe), and I just added 2 packets (they are cheap) in lieu of hydrating it. It worked out fine.