The contractor version is just that, the e-myth geared toward contractors instead of other business types. Not sure of any online resources or ebooks, but things that can be ordered online. Check out the PDCA's manuals.
Estimating Guide Vol. 1
Estimating Guide Vol. 2 Rates & Tables
The Business of Painting
Michael Stone's Markup & Profit
I'd also highly suggest joining NAPP, the National Alliance of Professional Painters.
They are an excellent source for the business end of painting.
There are a ton more books and whatnot out there, but I'd start there.
Also forums like these are priceless too.