Well, I know of a guy in the US that has a 32" EQ mounted scope built into his home...
here, and
here
If you were lucky enough to win a good lotto, well the sky's the limit. You can pick up a 40" OSG RC scope for $1-2million AUD. An OMI CC10 (40" classical cassegrain design) will set you back $460K USD (about $520K AUD, base price). Just depends on how much you want to spend
