Thomas - I have several of the small cookbooks issued by the Chronicle and also several of the "Dining in Houston" cookbooks that featured restaurant favorites, and I'm not finding the Sakowitz dish (I never had it). Have you tried the Chronicle? Go to the Food section (under 'Lifestyle and Features') on http://www.houstonchronicle.com.
I know they do a 'recipe quest' feature but I don't know how to submit a request.
I saw your post elsewhere also about the mustard at Nielsen's. I've loved that stuff for years, too. I think it might be what's called a champagne mustard. Here's a simple recipe I found on line: http://www.ilhawaii.net/~danrubio/mustard/recipes/panriver.html
There are also prepared products. Another thought would be to look for Danish mustard, if there is such a thing. The Nielsen's are Danish (they originally served smorrebrod when they opened in '52 or '53, but Houstonians couldn't figure out what to do with them so they switched to American style sandwiches).
I hadn't heard about their possible closing. Last time I went to Nielsen's, I thought the sandwiches and the potato salad weren't as good as I remembered.
Good luck finding the recipes. I understand Gourmet or Epicurious tried for years to get the recipe for Nielsen's potato salad and they'd never give it up.
Also, have you tried any of the copy cat recipe sites? CDKitchen.com and TopSecretRecipes.com are a couple I think.
If you find the recipe for the mustard, please come back and post or e-mail it to me