App Chef allows you to create universal binary apps by combining two or more apps. The first app (the actual app, not the binary in the ./Contents/MacOS/ folder) dropped in is the app that will be over-written after clicking on the "Create" button. This way you don't have to create a new app folder and put your resources, plist, and more back in. It supports Intel 32, Intel 64, PPC 32 and PPC 64 architectures. App Chef itself is a universal binary that supports both 32 and 64 bit OS.
Tested on Snow Leopard 10.6.8 and Mavericks 10.9.3.Download App Chef
I wasn't able to sign this app due to what it does. I will see about possibly using a temporary entitlement and see if I can sandbox it then.