It is definitely not possible to flash with dingo once you've flashed with the EE firmware on the PE. Believe me, toyz and I probably tried it like a hundred times.
Making the cable is really the only difficult part. Opening the case is super easy if you have a #0 screwdriver. And as long as you don't try to remove the motherboard, it is highly unlikely you will break anything.
The only fix that will be ever be available for this break will be via serial, because your buttons will no longer work to get you into the maintenance kernel. Sorry. In the future, if we are able to port clockwork mod, if you have installed clockwork mod FIRST, you probably can fix the problem without going to serial. But you will not otherwise be able to.
What's your general location? Maybe someone will be kind enough to loan you their cable.