the Ibis Bow-ti is a full sus bike without a pivot, looks a bit like them old kleins! I don't think flex would be a probably, because the bow-ti is designed to flex and no doubt that xc frame you rode was made to be superlight weight, super thin tube bike, so would flex a bit.
mike
http://www.encycleopedia.com/index.cfm?pid=23&edID=205 << Ibis Bow Ti Link