AU engine into EF/EL can be done and there is an eBay user called Aussiespares that sells AU engines with the sump already modified.
AU FORD FALCON MODIFIED ENGINE TO SUIT EF & EL - eBay Falcon, Ford, Car Parts, Cars, Bikes, Boats. (end time 05-Feb-08 13:59:19 AEDST)
Still simpler to just use any EA-EL engine if you don't want to pay for sump modification. I would go for the AU engine though.
