I have to say that GIMP is NOT the equivalent of Photoshop. I have owned PhotoShop since version 4 and own several CS suites. We work with quite a few customers who have Windows, but would like to move to Linux as it is genreally faster, more stable and reliable. We would love to see the CS suite or, at least, Photoshop, Dreamweaver and Indesign on Linux.
I would like to point out a few things. Most web developers are designing for *nix web servers. Most web servers are Linux. A 2009 Security Space survey found that Linux was installed on 60% of web servers. A 2011 Survey by W3Techs found that Linux was on nearly 64% of web servers while Windows occupied a mere 36%. A 2012 Netcraft survey found Linux (Apache and nginx) up 40% to a total market share of 76% on web servers. Microsoft's web server market dropped 15% to a 13.66% market share. Now, most web designers, although designing for Linux servers, use Windows because they need PhotoShop and Dreamweaver support. As nice as CrossOver may be, it is not the equivalent of native software. I have tried it and found it lacking. I think there is a large demand for Linux support from Adobe in the design world. The trouble is that we can't get the software to make desktop Linux a reality for commercial design.
This issue has been pressed here before and it has met with a large amount of resistance from Adobe. Adobe cites the lack of a viable Linux user base as well as lack of maturity of the platform. I would suggest a novel idea to test the validity of Adobe's position as well as fund development. Crowd funding is all the rage. If Adobe were to create a crowd funding campaign to port Dreamweaver and Photoshop to Linux, they could get a REAL reading on Linux support as well as get funding for the development. For example, if Adobe said they would start porting PhotoShop if they got $250,000 in crowd funding, I bet they could get it. If you really want to jump start the effort, offer donators a double the donation discount on purchase of the ported product. I would bet that you find more support than you could imagine.