The Hughes Easel 
I've used and researched many easel designs and have even made a few smaller ones myself.  The absolute cat's meow, in my opinion, is the Hughes Easel.  As an Industrial Designer  by education, I appreciate well thought out designs and the concept of an easel presents some interesting design challenges.  In my opinion, the Hughes Easel elegantly solves everything I have found lacking or cumbersome in other easels.   
I have a Model 3000 that is at least twelve years old, but it looks like the current 3000 is unchanged.  Here is a picture and link to the Hughes website:     

Hughes website 

Unfortunately, this is not a money saving easel solution, but if you want an easel that can be adjusted quickly and easily, this is your baby.  The big advantages are that you can instantly move your painting laterally or vertically with one finger due to the counter weights and rail system on the back side. 




I don't know if they make anything smaller than this, but I believe they have at least a couple of larger models.




Landscape Art Gallery 1 , 2 , 3, 4 , 5 ,  6
Abstract Art Gallery 1 , 2 , 3 , 4 , 5 , 6 
Aquatic Art Gallery 1 , 2