I'm not sure why you'd need a sledge hammer to remove the t-bar, and I hate to think of what kind of damage you'd do trying to use it. If you don't have a HD pry bar, maybe you could grind a chisel like edge into one of the hexes of one of your old t-bars (as long as they're not 340 or BB t-bars) and fashion yourself a reasonable facsimile of a store-bought pry bar.