This sort of thing does the job well:
http://www.bintel.com.au/Binoculars/...od-Adapter/34/
Andrews may have one: go here and scroll down
http://www.andrewscom.com.au/binoculars
- and a really strong one here:
http://www.telescopes-astronomy.com.au/ - but maybe overkill for 10x50's...
PS: This one is cheaper but looks quite strong:
http://www.ebay.com.au/itm/Brand-New...d=861395973812
- and finally: I can't see any reason why this one wouldn't work for 10x50's:
http://www.ebay.com/itm/Metal-Univer...14557862&rt=nc