AusBonsai

I have seen a few of these somewhere and I think I might be able to convince the owner and dig them out but not sure what they are and if they are bonsai material.

Looks like acacia to me

I'll have a stab at Acacia floribunda.

Then it wud be good for bonsai purposes i suppose

It would be useful if you could provide more information. Where abouts are you? Are these wild plants or planted? What is the habitat like? What other plants are around? What soil type and colour is on site?

There are HEAPS of species in Acacia and The more information you can provide, the more likely you will receive an accurate ID.

A. Floribunda

We are seeing some good acacias as bonsai now but they have been notorious as not coping with transplant when established so these may not survive attempts to rehome them.
As Jow pointed out, a lot will depend on the type of soil, etc.
Anything is worth a try. Hope for success but be prepared for the alternative. Keep a record of your procedure and let us know the outcome if you decide to go ahead. All info on natives as bonsai is valuable at this stage.

A few acacias will produce buds on bare wood but many will not back bud. This one looks robust so hoping it is one that can bud for you.