Can anyone recommend where I might find an incall that would satisfy what I'm looking for?

Sorry for being naive, a bit new to the Boston landscape.

Are you looking for a certified massage therapist or someone who is knowledgeable in body work. (Offering a massage without a license is a felony, this is why I ask.)
Let's assume your interested in bodywork. There are ladies, when requested in advance, may provide the service you're looking for. However, I know it's no easy feat to find it in a TER search so ask ladies you are interested in meeting. Be realistic.
Otherwise, go to the regular AMP and ask to have that service for extra.

All the best and luck to you!
AR
XO

You may want to check out the Mass and RI boards on the USA Sex guide.  There is a lot more MP and AMP info on that board and it seems to be reasonably up to date.