xONE4 starting point
 

What’s the cheapest place I could start an L/DONE4 from? (I’m based in CBR)

No difference anywhere within Australia - the price is the same.

Big difference (both in terms of cheapest locations and absolute price) for LONE and DONEs.
Australia is not too bad for a LONE4 and when positioning taken into account probably the cheapest for you.

I believe South Africa still leads the DONE4 race. Pakistan and Sri Lanka cheapest in Asia and NZ still cheaper than Australia.

Use this spreadsheet for most current prices:
http://sites.google.com/site/rtwfares/home

New Zealand is cheap for a LONE4 - NZD3799 (~AUD3170) compared to the Australian price of AUD3699
and the incremental cost of a LONE5 over a LONE4 is only NZD300 (~AUD240)

Significant savings in fuel fines can be achieved by ticketing with either LAN (e.g. start with AKL-SCL or AKL-SYD but with LAN not QF) or AA (i.e. start with AKL-LAX on the AA codeshare on QF metal). I costed up a LONE4 itinerary using the OneWorld tool starting with AKL-SCL on LAN - the total cost came to less than the base ex-Australia price

Sagy's spreadsheet is useful. It shows that New Zealand is the 3rd cheapest place for LONE4/5s and that Sth Africa is the 3rd cheapest for a DONE4 (and that Australia is the most expensive:eek:)