Ragtek is not doing custom last I heard.
Fuhrmann is good but very busy lately.
Haven't come across AlexD.
I recommend Waindigo - he's done brilliant work for me over two big addons and several small ones.
Not only does he find solutions for what I want he finds ELEGANT ones that work WITH the XF core.
He is unlike a lot of coders, he's able to see the user point of view.
His Library add-on is gorgeous (stage 2 arriving by end of this week)
I value the fact he's 'friendly' very pleasant in communication and explains what he's doing. Never talks down to me.
Support for any problems I have is fast and efficient too.