Actually, tire sourcing problems aside, the Tyrell P34 was pretty successful for a brief time until the ground effects era negated any multi wheel advantage.
And I think the FIA made the issue moot after the Williams experiment shown above, outlawing more than four wheels.
Ferrari also briefly toyed with the 6 wheel concept, but with two wheels in tandem per side on a single axle. Another idea lifted from the mighty Auto Unions...
Tim