Sentoryu has certainly been the most successful sumotori in mma.
i've actually been trying to collect a list of guys with sumo experience who have competed in mma. i'll copy and paste from a post i made earlier, and add a bit:
at the moment i have the following, more or less in order of rank achieved in sumo (with their shikona as sumo database links when applicable):
Kosaku "Iro Zeki" Shikimasu (high school sumo champion)
Emmanuel Yarborough (1995 Openweight World Champion amateur sumo)
Robert Paczkow (2001 and 2002 Heavyweight World Champion amateur sumo)
Alan Karaev (2002, 2007 Openweight World Champion, 2012 Heavyweight World Champion amateur sumo)
Kazuki Nojiri (former Jonidan
Wakamusashi)
Katsumi Yamada (former Sandanme
Wakaarashi)
Katsuhiko Kumago (former Sandanme
Kumago)
Teila Tuli (former Makushita
Takamishu)
Amaramend Boldo (former Juryo
Hoshikaze)
Noriki Miyashita (former Juryo
Hidenokuni)
Osamu "Tachihikari" Kawahara (former Maegashira
Tachihikari)
Shinichi Suzukawa (former Maegashira
Wakakirin)
Seiji Ogura (former Maegashira
Daihisho)
Henry Miller (former Maegashira
Sentoryu)
Yukio "Tamakairiki" Kawabe (former Maegashira
Tamakairiki)
Tadao Yasuda (former Komosubi
Takanofuji)
Yoichi Babaguchi (former Sekiwake
Wakashoyo)
Koji Kitao (former Yokozuna
Futahaguro)
Chad Rowan (former Yokozuna
Akebono)
and then these guys, who i don't think have any professional or amateur sumo experience (maybe high school level experience) but are notable fighters with sumo backgrounds...
Mizuto Hirota (not sure, but i believe he has at least some sumo training in his background)
Takenori Sato (5 years of sumo experience, don't know much beyond that)
Lyoto Machida (not sure exactly, but some experience in amateur sumo competition)
Kiyoshi Tamura (again not sure, but he has sumo training in his background)