As per my understanding, I don't think you can configure as such item wise budget in standard.
you can assign budget on basis of
Cost Center(fund center) - G/L
Profit Center(fund center)-G/L
AUCs(Fund center)- G/L
etc.
so when you will create budget system will derive details on the basis of above details.
you may do some Z code/BADI/User Exit program for your requirement