I have been looking for one without speakers as well and haven't found any. In fact, when I do my search, it usually brings up the same question being asked in other forums of various types.
I have an email into Crutchfield regarding this to see if they can come up with anything. I'll be happy to pass that along.
BTW...when searching, I did find one unit with speakers that still had the "old" hookups so a converter would not be needed.
Question: In a motorhome, how many watts to the speakers is "enough" for a good quality surround sound experience. Don't need to blow the doors off, but want to be sure I'm not going with too little.