The largest and most common 16" autocross tire is going to be 225/50/R16, which is approx. 25" tall. The top 3 tires right now are Bridgestone RE-71R, Yokohama A052's, and Falken RT660's from what I've heard through the grapevine. The Yokohama's do come out in a 245/45/R16.
I would say, not to worry about looks if you're serious about going fast in the autocross. Tires are the best upgrade you can make to go faster. If looks do matter that much, just get whatever tire gives you the look you want. At the end of the day, no matter what tire you get, what matters most is seat time.
If you're not running in SCCA CAM-T and your class allows you to run something less than 200TW, it seems like Toyo Proxes R888R (100TW) comes in a 245/45/R16 & 255/50/R16.
