Myself and chop5 do the capacitor changes (I believe there are others too, just not sure who is actively offering them right now) I do the region mods as well, but I'm out of IC mod boards right now (have some on order) So it may be a bit before I can offer that service also.
I generally don't charge squat to do em
Its more of a community service. I usually just charge return shipping + the cost of parts (usually $10 or so for capacitors, and about $15 or so for region mods) It takes me about 3 to 4 hours to do a capacitor swap and another hour and a half or so to do a region mod. I should be caught up enough to do another duo here in about a months time if you want to contact me then! In the mean time, play the junk out of that duo!