Most of the fees included in the final "out the door" price are also out of the dealer's control, so you're unlikely to have much luck there, either. The only fee that's directly in the control of the dealer is PDI (sometimes called setup or prep) and is the amount of labor spent uncrating the bike and getting it ready for sale.
Dealers might be willing to negotiate the price of a discontinued model, but likely as not the specific bike will already have that discount reflected in the price.
Many dealers, however, have been offering unprecedented discounts on new scooters because of slow sales in 2009-10. These prices are usually advertised or marked on the scooter on the floor. These discounts will likely disappear as the scooter market recovers and new models are introduced.
While it's certainly acceptable to ask about discounts or other offers, haggling is fairly unusual. If a dealer is unwilling to budge, don't take it the wrong way. They're certainly not getting rich selling scooters. It's far more important to build a positive relationship with your dealer than getting a "good deal" on a scooter.
Other markets differ.