It might be possible, but even weber puts an axle on the smaller plastic wheels, I think the install would be sturdier the way the OP did it. I have a newer performer with a round tube frame. Looking at the thickness of the metal I wouldn't trust doing that without an axle, the stainless performer might fair better.Just a thought??
DO you think that the full width axle is really needed? I wonder if one could get away with independent bolts at each corner? I am probably complicating this but that's what working nights does to you