In the absence of the availability of the typical ARF warbirds from the large manufacturers that are available from the low labor cost areas of the world,
There are at least 4 or 5 individuals participating in the SAMs race series that have designed and tested their own planes for this series.
I'd suggest looking them up and seeing what they have to offer.
The Coach (Steve N) and Tim Stafford are two individuals that come to mind that have designed good looking, very close to scale planes that are competitive in this type of event.