If you can find a reputable book, cash, bitcoin, or whatever that has odds for sumo wrestling or any odd sport, I can accept your bets but the juice will be higher of course unless already really high. Like if the odds were -110 / -110 on the book you find sumo wrestling, best I could do would be -116/-116. If its -120/-120 on the book you find, I could do -120/-120 too.
If you would be wagering daily or multiple times a week, we could set up an escrow to hold 5 or 10x the maximum amount you plan on betting and settle weekly or whatever.
The above^^^ goes for anyone I like the occasional gamble on crazy sports like Aussie Rules for example, so if you got a crazy sport let me know and I'll see what I can do.
Im pretty sure many of the sports sites would host that bet happily, where do you watch the matches ? got a link to a stream ?
Been a fan of sumo wrestling ever since watching blood sport (hehe i know, not accurate at all etc etc).
But now we have only some "pay-per-view" as you can notice here:
www.sumo.or.jp/en/kyokai/information?id=26
http://www.ustream.tv/Sumo-Daily
P.s.: do not expect HD quality though...