IFollowRoads
I would just check the reasoning behind the engine being condemned.
I had a PA28 for a while that had recently been zero houred and the oil usage was about the same, 1 litre per 5 hours. I had this checked out and two independant engineers both said that there was nothing actually wrong with the engine. It carried on like this for a while until I sold it (for other reasons) and as far as I know the new owner is still having plenty of hassle free flying.
I really would consider a second opinion. The levels of oil usage you are talking about are not THAT high and may not be a bad thing in the long run (except of course for the added fixed costs of 200 ml of AD100 per hour!).
M