I think Jo Connolly of Dreamtime Kullilla at Redcliffe (north Brisbane) and Dilly Bag does bush tucker/bushfood catering or would be able to help you out with your query. Dilly Bag was at the Sunshine Coast but I'm not sure if they're still there.
Best to contact them and I'm sure they will help you out. I would probably try Jo first but it's up to you. I believe Jo and Dilly Bag liaise with each other closely. I think their businesses are closely connected but I'm not 100% on this.http://www.dreamtime.auz.net/
and look at bush tucker. To contact Jo, look at the contact us page.
and there's http://www.dillybag.com.au
who has a page on do-it-yourself catering .
About the bushfood cake, I bake cakes & decorate them, plus made some bushfood cakes (not a registered business, home baker only). If interested, send me a private message & supply more details.