My RV-8 came with an Aviation Products tailwheel and a 6 inch wheel. It's very robust. Has a 5/8 inch axel. Here's a link:
http://www.apitailwheels.com/products/products.html
I'm happy with it.
Building a RV7 QB and have been told there are. Better options for off pavement tailwheel ops. Any info appreciated as I'm first time RV builder but have built/rebuilt a few dozen tube and rag cub type taildraggers. Thank you Dave