You might be able to fit a '98 rear bumper setup on your '99. They are the same chassis, so I imagine they would have the same mounting holes. The '98 had a metal bumper that was covered with a plastic cover. You could actually just use the metal bumper alone if you wanted to...it doesn't look as clean though.
Just a thought...
2006 Arctic Cat SnoPro 440/700 EFI
1998 Arctic Cat ZR 600 EFI Custom
1996 Ski-Doo FormulaIII 600
A mountain lion roaming the prairie found a bull, killed it and ate the entire bull. With a heavy belly, unable to walk, the lion laid in the tall grass moaning and roaring. Soon a hunter, attracted by the roaring, shot and killed the lion.
Moral: When you're full of bull, keep your mouth shut!