I know that this is a long shot, but I figured that if there is an answer I can find it at this website. My 10 year old son's favorite character on Star Trek is Lt. Riley. He really wants a Lt. Riley action figure to add to his collection. I told him that I doubted that such an action figure had every been made, but decided to post the question to the BBS. I'll take you home again Kathleen.....
T'Bonz just had a Cubify figurine made of herself. I'll bet they could make a Riley. But they might not do it because actors' likenesses have to be licensed.
Can I just demonstrate why I'm the worst mother in the world. A lot of action figures don't look anything like the character. Could you get a really bad Chekov figure, substitute a Sulu shirt and say its Riley? You know unless you want to be a role model to your child or something like that. LOL. You could also tell them you are making a Riley figure for them. He might like you putting in the effort.
The key to a really great custom figure is to find an action figure head that already has an uncanny resemblance to the actor you need. I've made a Dr Selar from a K'Ehleyr figure, who, of course, looks like Suzie Plakson (second from left). Star Trek customized action figures by Therin of Andor, on Flickr