Huw, there won't be a wiring harness for that simplistic of a scheme, just wire that one up yourself I think. If you need some help I'd be happy to draw it out. That situation is pretty simple and for these types of jobs I use some of these weatherproof connectors:
http://store.summitracing.com/partde...5&autoview=sku
You can get them in 2, 4, 8 pin and more versions and work well. As to a coil I recently purchased a MSD vibration proof coil, but that is going to depend on what sort of ignition system you'll be using.
Ron