Has anyone used something like this

[jay see]

http://www.ebay.com.au/itm/221307810982?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

In the Built-in GPS navigation part click on more information. It says that you can run OziExplorer

[threedogs]

You can do better than that try and find what "Eonon" have to offer.
Think that's right, My head unit does the lot as most do these days
CD. DVD. MP3 TV. Ipod. Bluetooth, am-fm, GPS, USB, SD card 4gb thinks that's it, all for around $300
with a 7" screen

[the evil twin]

OziExplorer will run on Windows CE or Android so, as TD says, probably 99% of the GPS capable head units on Ebay will do the job.
Just make sure the one you pick is a dual zone and choose one that suits the look/budget/colour/layout or whatever you prefer.
Personally I prefer a head unit with a volume knob rather than soft keys... easier to adjust on the fly

[Bloodyaussie]

I have a 7inch Chinese gps that I run oziexplorer on and have nearly every map in the country.... except bloody tallarook and cobaw???

Have still not field tested it yet as I got it the weekend after the toolangi trip.