One Joint that come to mind in Sydney is Sefton Smash Repairs. The bloke there did some very nice custom work on my mates Crappadoor Trayback ute. So much so that he was invited to a ute show in Melbourne to display it.
You are really chasing a workshop that doesnt deal soley in insurance work, they are only interested in high turnover quick work. You are after a workshop that prides itself on rebuilding/customising your pride and joy. Google a few joints and make some phone calls, a quick chat to each joint will soon tell you if you want to hand over coin to them.
Just a quick google of "custom panel and paint" showed up
or take a look at this link from HOK paint and call a few of these guys. http://www.houseofkolor.com.au/automotivepainters.php
You might find it hard to get much feed back as allot of members do the work them selves to save their coin, me included... :)