So if you actually want to find executable file types (e.g. scripts, ELF binaries etc.. etc..) not merely files with execution permission then you probably want to do something more like this (where the current directory . can be replaced with whatever directory you want):
gfind . -type f -exec bash -c '[[ $(file -b "'{}'") == *" executable "* ]] ' \; -print
Or for those of you who aren't using macports (linux users) or otherwise have gnu find installed as find you want:
find . -type f -exec bash -c '[[ $(file -b "'{}'") == *" executable "* ]] ' \; -print
Though if you are on OS X it comes with a little utility hidden somewhere called is_exec that basically bundles up that little test for you so you can shorten the command line if you find it. But this way is more flexible as you can easily replace the == test with the =~ test and use it to check for more complex properties like executable plain text files or whatever other info your file command returns.
The exact rules for quotation here are pretty opaque so I just end up working it out by trial and error but I'd love to hear the right explanation.