There are plenty of smiths/rifle builders on here who'll do the job. As to how long, some of that'll depend upon how busy they are @ the moment. And cost will likely run from say $65 to twice that. Although those numbers depend upon whether or not you already have pillars in the stock, or if you want them installed at the time. In which case, the $ numbers get a lot higher, as you're going to be paying for a bedding job as well. Though, IMO when doing a re-inlet for floor metal, I prefer to bed it into the stock just as you'd do with a barreled action.
However, if you're handy with tools, & are a cool hand with a Dremel & Devcon, you could do it yourself in a couple of hours.
In terms of smiths that'd do the job, take your pick. Them, & or one of the custom stock makers like Manners can do such mods. => Look in the vendors section as a start.