Absolute best locking tuners I've used are Hipshots. You can get a million different button styles, including vintage "bean" shaped. They can be had regularly for around $50-60 a set, are beautifully made, and work fantastically. I don't even consider others any more. I get mine from a place called SportHiTech (also on Ebay and Reverb). No affiliations, just satisfied after something like 7 sets from them. They make up custom sets as well, usually for no extra cost.