I'd put everything back together the way it goes, with a new fuse, and start moving wiring around under the dash and in the column while someone watches the speedo.
Do thins with the ignition on, motor off, and see if you can get a reaction from the speedo while doing this. If so, you may be able to narrow it down and find an unwanted path to ground or a wire pair that are crossed up.
If that didn't show me anything, I'd pull all the relays other than what is needed for basic operation, and drive it. I'd put them back in one at a time until the problem returned, then start looking real hard at that circuit.