Thanks for the quick responses.
To Rivets: I should have included this info in the original post, but I had already been looking for the 694315 tank. They appear to no longer be in production, and stocks appear exhausted. I did find a used one on ebay but, at $255, I decided to pass on it. Carburetors are no problem, as Chinese parts are widely available. Trouble is, the carb without an intact tank just won't do the trick.
To Mechanic Mark: Thanks for the search links. As I mentioned, carbs are not a problem. The tank search provided a multitude of links, most of which I had previously visited. There was one new site that showed parts in stock at reasonable prices, but seems really sketchy to me. Throwing caution to the wind, I decided to order from them. There appears to be a problem accepting my credit card, so the order is in limbo for now. I'll post a report with final results, regardless of how it turns out.
In the meantime, if anyone reads this that has some experience in 'adapting' another type of tank/carb combo to this engine, I would really like to hear from them. I have little confidence in eventually finding the correct fix.
Thanks!
cc.shankslawn.com