steve,
the profit margins on the '07 1098 is slim. (the dealers had their margins cut after the price was set and were not allowed to increase the MSRP - at least that's what my dealer is saying). since the salespeople work on a commission that is based on the profit margin as opposed to the sale price, the commission on the 1098 is not very big. while your 1098 may be one of the most expensive bikes on the floor, your salesman very likely makes a much bigger commission on other, less expensive bikes that have more mark-up in them, (used bikes, for example). that being the case, your salesman was probably very grateful for the tip. and since they're delivering your bike, (on a trailer, i hope!), it's only fair. some dealerships charge a delivery fee.
i used to sell cars before i went to lawschool. i made a living but it was no get-rich-quick scheme. i was very grateful on the rare occassion when a customer gave a gratuity. you did a nice thing. that can never be wrong. and you're making art on top of it! good for you. you get my vote and my business if i ever custom-paint my bike!
Elton