I just had this done on my Beretta 687. I used a gunsmith in Quebec who I just had my third shotgun job done by (steam stock bending for cast/drop, custom pad installation, part replacement etc...). I just say that I'm very happy with the results, especially of this most recent job. He offered me two different finishes - the regular finish 235$ (4-8 coats, "matte") or the Master finish 335$ (10-18 coats with better polish - a bit shinier). I shelled out for the Master finish because this gun has particularly nice furniture, and I don't regret it. When I brought the gun to him last summer he told me to take it home, hunt it for the fall, then send it to him over the winter when the relative humidity was much lower and the oil would take much more deeply. From a cosmetic point of view the results are outstanding. There is a lot less "yellow" tinge to the wood - bringing out the brown and gold a lot more. I'll take a few pics but they won't do it justice - in some light the tiger-striping pops out, and on other angles you see the deep marbling. Anyhow, cosmetics aside, the grip is much more secure than it was on the varnish. Also, areas of the stock that were not varnished (and therefore not protected from moisture), are now oiled (inside the forestock, all wood/metal faces). Of course, unlike varnished finishes, I'll be able to buff out any of the inevitable scratches (this is my pheasant gun, so they will happen).
Anyhow, the gunsmith I used is Alain Combes just outside of Montreal. Based on all the work I've had him do so far, I recommend him without hesitation.
http://www.armurier-quebec.com/indexgb.html
-DW