Woow, from my searches, I don't think there is a flanged type bearing for the size you're looking.
However, for a normal metal shielded bearing of 5 x 8 x 3, you can look here at http://www.minibearings.com.au.
Go tot the search function and click on the size. Key in "bearing" and the keyword search and type in the dimensions.
It's pretty expensive though... What is it for?