My biggest problem turned out to be finding large pieces of seitan. It seems my Whole Foods and Central Market are often sold out. Urgh! Instead, I decided to live dangerously and substitute tempeh; plus, I'd never had it before so it would be an adventure all around. Tempeh comes in several flavors and can be found pre-marinated. I chose a 5-grain version for my piccata. The other most important ingredient is the wine. A dry white wine works best and you don't have to spend a lot of money! My newest discovery is Vieux Papes, Frances most popular table wine. (Sorry, the website is in French; so dust off your high school French-English dictionary!) You can purchase these wines at Whole Foods and they typically run around $5-6.
Full recipe here.