I have 3 clown loaches in a tank with one Gibbiceps plec, and one Royal Plec, never had an issue with them. If anything, the Clowns and the Gibbiceps are friends!!!
I do have a question though - would it be too much to put 3 bristlenose pleco and 3 or 4 clown loaches in the same tank? This tank is only 3ft in length, which I'm sure is too small for clown loaches in the long run, but I have plans to accomodate them eventually.
I was getting a little concerned as I read an article about the clown pleco and it said that they didn't get on the Botias because there diet was very similar and they might fight.
My Clown Plec (L015) gets on with my clown loaches and also lives with them under the bog wood and seem very happy.