You could always use Bundles -> Textmate -> Show Keyboard Shortcuts or press Cmd+Alt+Ctrl+K and then you get a functional window with your required info.
This is a nice feature, but what would be really great is a window like the Go to File and Go to Symbol symbol windows for Execute Command that would present a list of commands allowed in the current scope. This would be a nice alternate way to invoke commands especially while learning a new bundle.
Matthew