Newcomer,have you tried down at Kingaroy.
He's got several hundred.
Also,Baramba deer park dispersed their herd several years ago, the new owner may have some leads on Qld breeders & the old owner who owned & sold them still lives beside the park.
These were originally from Gatton Uni stock when the deer unit was going & much ,much more fecund ,healthy & from a broader genetic base than the stock held in zoo's currently.
They are more difficult to keep healthy than pure elk are & hard emotionally too as they get you in,so be warned most populations fail.I blame MCF for most failures, so keep any sheep well away.Also everything likes to eat them especially wedgetails.If you see a mob together it's my belief they are always discussing a novel way to commit suicide.I'm serious.
If your hart's not set completly on blackbuck wouldn't hoggies,rusa,chital or sambar be a better option,but then I guess you'll also want them too.lol
Are you also aware of the new risk assessment "Bomford indicies" & the vertebrate pest management authorities (national) position on increasing the category from 3b to 3a based on this flawed indicies.This is a blatent attempt to reduce the numbers held in private collections in Aust & will no doubt lead to the localised extinction of this species here.
Best of luck
Khakibob