Once I saw some really great traditional hats with cat ears-- one was a straw sunhat and one was like a bowler with cat ears, both were made for women so they might be a little small for some, but I recall them popping up on Amazon... I forget what search term I used, but it brought back cute hats.
I've got a knit beanie cat hat right now, and a fleece bunny hat where the ears are long enough to stand in as a scarf with a little strategic tucking-into-coat-in-just-the-right-spots.