Of course there's Ban Tang, and I recall Jeremy Horton does mods too, but I haven't the slightest idea of how much they'd charge. There's even a couple Scrap Yard forumites who are trying their hands at knife-making who might be able to help you. Based on the amount of work involved (if the work is done by hand), I've always assumed that the cost of professional mods would probably exceed the value added. It might be worthwhile to get a knife vice and some good files and do it yourself -- it might not look as pretty as if you sent it to a shop, but it'll be a learning experience and it'll be truly yours.