You can buy,
2 5x8mm flanged bearings
http://www2.towerhobbies.com/cgi-bin...?&I=LXD111&P=7
and 2 5x8mm un-flanged bearing
http://www2.towerhobbies.com/cgi-bin...&I=LXD109&P=ML
and that will work out great, you'll still use the standard clutch bells.