Varanus brevicauda AKA Short tailed pygmy monitor only grows to 23cm total length, making it the smallest known monitor, it is available on a NSW Class 2 license but iv never seen one for sale anywhere.
The Australian Reptile Park has them on display and id describe them as pink geckos on crack
the smallest python species is the anthill python [SIZE=-1][FONT=Verdana,Arial,Helvetica]Antaresia perthensis[/FONT][/SIZE][FONT=Verdana,Arial,Helvetica][SIZE=-1] [/SIZE][/FONT]