My buddy at the trails in Liverpool did exactly this to his FSR many years ago... was before the time that all these little 24" dirt jump hardtails were coming out, and we both had converted bmx cruisers into little hardtail jump and park bikes. He then went one better and built a full suss around an FSR.
It was, without doubt, the best bike to ride the trails... which included several Brooklyn Park Bikes, a Brooklyn Minilink, and a range of Cannondales and other stuff etc that were "built for the job"
Ground clearance was never an issue, and the handling was spot on!
G