I see that it's been quite some time since you posted this, and as I'm just beginning my research, I've just stumbled across it tonight.
Your post caught my attention because I am trying to find info on a great-great grandfather, R.M. Bruce, but am unable to do so.I seem to have hit a brick wall while researching him and subsequent generations beyond him.I do know (or was told anyway), however, that he was born in Georgia and eventually ended up in Alcorn Co., MS, as I've tracked his grave down online.He was married to Charity Belle Cox Bruce.
Some of the notes that were passed down to me by my late grandmother show his name as Raltamanus Bruce, while websites showing graves list it as Ralta Manus Bruce, R.M. Bruce and yet another website I've stumbled onto had his name spelled slightly differently from either of these.Because I've found so little on him, I'm not quite sure which is accurate.The timeframe (the mid-1800s, as you mentioned) fits my Bruce connection, too.
Anyway, I may be barking up the wrong tree, as I'm not aware of any connection to the family surname you referenced.However, as I said, I've found out so little at this point that there may be a connection that I've yet to discover.
If any of this information connects some proverbial dots with what you've researched, please let me know so that we may discuss further.