can somebody tell me if this is technically possible?
Easy,
2 different ways
Have a very low interest rate on Staking, and then burn the transactions fees.
You can burn more supply in fees, than is created by staking, thereby stabilizing the supply.
This can even decrease the supply over time as usage increases.
ZEIT is an example of this.
or
Don't have an interest rate on staking and only credit the transaction fees as a reward for staking.
Supply is a fixed constant and never increases or decreases.
NXT & ECC are examples.
* Most PoS coins based on peercoin's Proof of stake design burn the transaction fees.*