This 1958 Ariel Square 4 restomod is one of the nicest looking examples to be offered for sale for quite some time. It was recently treated to a complete frame off restoration and the seller made some very nice upgrades though all of the original pieces go along with the sale.
The Ariel Square 4 engine is interesting in itself. It's essentially two parallel twins set fore and aft of one another in a single crankcase with the two counter rotating crankshafts geared together. The counter rotation cancels gyroscopic forces and makes the engine quite smooth.
Though this bike is certainly not restored to its original configuration, I doubt very many would argue it's not extremely well done. I really like the look of it. It's for sale on eBay.