I was searching Jaycar's catalogue for general power adaptors for non astro stuff when I stumbled upon this adaptor which should meet most requirements for powering an EQ5/6 mount as well as some accessories. Comes with a cig lighter output and is rated up to 8Amps, not too bad a price (this isn't a plug, pardon the pun, for Jaycar but given mains power for EQ's comes up a bit in these threads thought it might be helpful)
12VDC 8A Switchmode Power Supply