Are they looking for a traditional style?
If so Keith Johnson or Luke Swenson come to mind. I have meet both and both do excellent work. Craig Brewer would be another, I think he makes lock backs to and is a good dude.
If you are looking for more budget friendly lock backs. Buck has made an array of changes to the 110. SK blades works directly with Buck and makes tweaks to finish and blade steel then Buck manufacturers them. I'm gonna pick up one of these. Light weight buck 110 with cpm154 steel for $40 https://www.skblades.com/product-page/the-smoke-jumper