I don't know about 'very rare' but they are not that common. Most Antaresia are kept in similar setups in captivity, so if you are having trouble finding caresheets just look on a Children's python care sheet.

A quick google gives me....

http://www.a1pythons.com/anthill.html
http://www.kingsnake.com/donpatterson/pygmy.html
http://www.antaresia.com/antaresia_anthill_python.html
http://www.smuggled.com/ant1.htm

That is the general info....