Just finished the Museum miniatures Hay Wagon, with Eureka horses. This was a fun little project and will be suitable for anything from Renaissance up to Napoleonic.
There needed to be a little bit of cheating with the scale of each part of this. The horses looked huge when compared to the figure and the wagon, so to boost the height of the other parts the figure and wagon had card under them to boost them up to so they looked better with the horses. This also helped the miniatures when sitting alongside 18mm figures.
Some of the pics are a bit blurry but you'll get a good idea how the wagon turned out.
I may at some point add a rope or reigns or something so the figure is pulling the horses and not thin air.