Alt, do you mean 1 amp draw for a regular MB-6582 or with your switching solution? I am using your recommended 5 V switching voltage regulator (http://www.mouser.ch/ProductDetail/Texas-Instruments/78SR105HC/?qs=sGAEpiMZZMtwaiKVUtQsNWWYJJUUxYbPRFCRyYymPj0%3D) where I am drawing about 200 mA with all LEDs lit. This is without SIDs so far, hopefully this weekend!
I found the back was a better place to mount it, this way the 7809 can heatsink on the huge ground plane. This works better for the 5 V pinout too, where the (redundant?) smaller smoothing caps are now on the output.
To Blatboy: as Wilba designed this with a C64 brick in mind, you have to solder a few jumper wires to get the power in off a single supply. You can for instance use the DIN7 socket and forgo redesigning the back panel. Check this thread for Altitude's work:
Just a note: your rectified 9 VAC will actually be near to 12.6 VDC once smoothed out.
9 VAC * 1.4 = 12.6 VDC rectifying and smoothing
12.6 - 2*0.7 = 11.2 VDC two diode drops
Should be enough for a 7809.