In the scale world, many items we must take what we can get then scale it to work for our build.  The L4 I built had a tailwheel setup that could not be bought off the shelf. 

As you can see from the below photos of the full-scale tailwheel I had to model.

All you will need is some scrap brass stock and a little soldering ability.

Take some brass and make a wrap for around the post for the tail wheel.  Make a plate for the top of part.  Look at the photos below for how it was made.   After you are happy use a wheel on a dreaml tool and clean up any sharp edges.  

For the wheel yoke, I also made it from scrap brass in my box,  Take a look at the photos below for ideas.  

Feel free to add support where you feel needed.  When everything is done, do some sanding and cleaning up of the part.  Also recommend a light over all sanding to help with the paint to stick. 

As you can see from the finish product its very close to scale. I have been flying this setup from the mid 2010 and have had no issues.