Can't comment on the breed advice - we are having our own problems making a decision as to which to get

However - gabions. We have used them to very good effect to build a retaining wall for our barn (our land is gently sloping and we had to dig in to create a flat site for our barn, we ended up with a 1.5m end retaining wall). You can get the gabions in various different sizes - we are using 1m by 1m by1m, and also 0.5m by 1m by 1m.
In order to get a good finish to the face we found it was best to pack the gabions by hand, you can't just dump the stones in because they will end up with big gaps or bulge outwards which is murder to remedy once the cage is full.
We have loads of stone in our field because it was used as a general dumping ground for the old cornish hedging stone when the farmer opened up the fields plus the remains from the old stone cottage - its a great way of clearing up and re-using the stone.