What you end up with here is a variation on a fork mount.
I have thought about this idea myself and there is a few practical issues to consider.
- For a person in Melbourne the base will need to be tilted 90-38= 52 degrees for the azimuth motion to become RA.
- considerable modifications to altitude bearings will be required to make them captive
- strengthening of the base will be required
- the scope will need to be correctly balanced so that the dob wont take off 'downhill' when pointing off to the side
- the focuser will end up at odd angles at different parts of the sky