I am registred to a Kalacheva online art school (russian) and this autumn they do a new free sketching extreme course. You get a lesson every other day and you work with a teacher on a different subject.
This course deals with sketching with markers but since I didn't buy them yet I've decided to work with some colored pencils.
Of course, the effect is not the same - and it shouldn't be, but it's still working a bit on a form, the sketching itslef and mastering the colored pencils.
As of moment of writing these lines only two of the lessons where published so I'll keep no updating as they get released.
I might also do these in b&w, see what happens.