Using flanged bearings is a great idea, you can kind of replicate the wildwood mounting plate with a bearing on each side and a transverse shaft. It's not hard to find steel and stainless steel keyed shaft online, keyed collars are available too.
http://www.surpluscenter.com/Power-T...-2982-50-3.axd
http://www.surpluscenter.com/Brands/...r-1-1563-A.axd