Its my understanding that publishers like to have a synopsis or "thesis," as you put it, along with say, the first thirty (30) pages or so. If they like that they will ask you to send more of the manuscript or the rest of it.
As for finding publishing houses, as you know, all you have to do is Google. You want to look for publishers that accept unsolicited manuscripts, not all do. If you have an agent all the better.
But then again I guess you don't have an agent. Otherwise you woulnd't have to ask us. My understanding is that after you send in part of the novel (with self-addressed and stamped envelope for return please -- if you don't send this along with return postage, they won't touch it).
Lastly, since publishers are inundated with many thousands of manuscripts, I would say you're in for a wait time (after you send in the manuscript) of between four to eight weeks, if not much longer.