Try Michigan Iron, they make thumbs (and grapples), and are quite reasonable. I bought one from them for my Kioti 2465 back hoe and haven't had any problems. You can look at their web site, I think there are pictures.
Try MANUFACTURER OF QUALITY SKID STEER ATTACHMENTS , I bought a grapple for a miniskidsteer and adapted the mount to fit my Yanmar excavator. They also make thumbs. It depends on what you are going to do with it, the grapple I have is 27" wide and I can pickup a bite that will fill a pickup with brush in two passes.