I have the 100L macro, and you are getting comparable shots with your setup. I would just think of adding a Canon EF 25II Extension tube just to get a bit more magnification.
I'm thinking about getting the 100MM f/2.8L but I'm not sure I'm a huge macro guy. Might just grab the regular 100MM for 1/3 of the price. The extension tube will cut out too much light for the 17-40MM, so I don't think I'll go that route. Thanks for the input though!