The availability of A123 in Australia has been the second major stumbling block, however after seeing another guy at my field experimenting with packs that he had imported from the USA I decided that even with the expense, it would worth the extra cost to import them for use in my next project. However I have seen that Fromeco has just released both original and generic A123 packs so Howie at DA should have them soon. Also the same friend who imported the packs tells me that DeWalt are about to launch their A123 cordless system in Australia and a lot of people are stripping down these battery packs to make home made RX and ignition packs. There are a lot of build threads here on RCU and on F l y i n g G i a n t s on how to build these home made packs.

Just to add, if I was you and I was having no problems with my NiCd packs (and not running Spektrum/JR 2.4GHz) I would not bother changing them out with A123 packs (or any other type of batteries such as LiIon/LiPo), the weight savings of a few grams is not worth the expense IMHO. When you have to replace them or you are starting on your next Giant Scale project then I would consider the A123 packs. (I assume that you are using 6V packs)

Cheers
Pupmeister