I have installed a tile floor in the bathroom. The tile is 1/4 inch above the cast iron stool drain. I was thinking of using an extra thick beeswax seal. If this does not work, is there a spacer made to extend the cast iron flange?

There are many different designs that all will meet your needs. This is but one Set-Rite Products - Toilet Flange Spacer System (http://www.set-rite.com/)

I have installed a tile floor in the bathroom. The tile is 1/4 inch above the cast iron stool drain. I was thinking of using an extra thick beeswax seal. If this does not work, is there a spacer made to extend the cast iron flange?

A extra thick wax seal with a funnel ,(see image) should work since the horn of the toilet bowl extends past the flange.
If you're concerned you can raise the flange wit a set of flange spacers.(see image). Good luck, Tom