Renting a good instrument short-term is not going to be a solution because you need to get to know an instrument really well if you are to perform well on it.
Buying a violin is going to be a very complex process...and it might take a while. The problem is that my usual method of roaming the internet won't help me here...
So I'll have to think about finding a way to get started...but there is always some fun involved in looking for something new...although it usually stops when ou are asked to hand over 15000+ Euro...which is about the starting range of good modern violins...if you look at old instruments you can add a zero or two, but that's more than I could (and would consider) inviesting...