When I was getting quotes I tried these two. Both with in $50 on the quote. $450 and $500. fix dent and one colour. They quoted off a pic of the damage. Never went through with it so no opinion. Asked a couple of bodyshops I deal with through work and $500 was average. About 2-3 months turn around in NOT busy season.
I usually paint my own stuff (don't ask -- I don;t do this for a living), but when I need a top quality job I found 2 places in Markham. You can't call because these are body guys that do it on the side. There's an old fella at Sunnyside Auto, 185 Bullock Drive, he's a master paint matcher, he used to do a lot of custom bikes. He quoted me 1 to 4 cases of beer + the cost of paint depending on the condition of the tank.
I also had a base/clear done on a Suzuki Boulevard tank and side panel at Markville Autobody a few years back. Sent me to get the paint ($25), he charged me $100 to prime, spray and clear a tank and 2 side panels. I did my own filling and fairing.
Any small body shop can do it, find one that's not to busy and you can probably get a tank with minor damage painted in 2 days for less than $200.