We recently rented a campervan from Autosleepers.com.au who are located in Banksia in Sydney.
The campervan was a 4 berth Fiat Ducato which was equipped with 2 double beds, a kitchen area with hot and cold water, a toilet and a shower.
The Fiat had 240v power along with 12v, was air conditioned and came with all of the linen, cutlery, pots and pans and camp chairs etc that you need to have an enjoyable time away.
I would definitely recommend taking your family away on a camper holiday. For our camper adventure we went to Hill End in central NSW. The family loved it, sitting around an open fire in the evening while still having a lot of the luxuries of home.
The guys over at Autosleepers were great and really took the time to make sure that we made the most of our trip away. Other campervan hire places that you could potentially look at are Britz.com.au, Camper.com.au and apollocamper.com.au.