Yep, Dresser's got 'em for $59.95. It is also been on my buy list for a while since the old 6 inch tire looks more like 4 1/2.
This got me thinking a while back about substitutes.
Since the Crusair is under CAR 4a, which specifically says that the tail wheels need not be of an approved type, there may be more options. Matco, for example, has a pneumatic 6 X 2 Wheel and tire for ~$75. A replacement tire/tube is ~$16 for it. Has anyone "gone experimental" in this small corner of our world?