Actually, built somewhere around 5-6 hundred of them. In some cases it is possible to use a longer rod with a stroker crank, but that is also dependent on the stock rod length, the current compression height of the piston, and the amount of the stroke increase. The length of the rod used has no bearing (no pun intended) on the strength of the crank, only the amount of stress applied to it. The crank is what it is, strength wise.
I never said the rod length had anything to do with the crank strength. I did make a mistake with how I worded the first method of stroking a motor. That was supposed to say that you can increase stroke with a stock crank, by offset grinding. Offset grinding the rod journal moves the centerline of the rod journal away from or toward the centerline of the main journal. This will result in increased or decreased stroke. This method weakens your crankshaft.