Try a Hydro Flask with a Klean Kanteen sippy cup adaptor. I just ordered a Hydro Flask and already had a KK. I tried putting the KK sippy cup adapter into the Hydro bottle and it fit!! It's the PERFECT bottle now for my 18mon. old, I'm so happy and trying to spread the word to other parents out there!
Oh I got a 12oz. size Hydro Flask.