For me a sling shot comp would be a great comp (mini comp) to go with a real bench press or powerlifting comp or even as just exhibition lifting to go along side a bench or pl comp - I feel that some ppl would see a full on sling shot bench comp as abit of a joke - but as a side thing or exhibition I think it would be great and if there was a seminar by Mark Bell it would draw some more ppl.
I may be wrong and maybe this is the start of a new div in powerlifting...but really I think the sling shot should be a training tool and thats it...