Plenty of brands. Asics (EUR 48), Adidas (47 1/3), Mizuno (46 2/3). Yonex (47), Babolat (48) and Nike (47.5) have 31cm but no 30.5cm
I can highly HIGHLY recommend the Nike Kobe basketball low-tops. I wear the same size (US13) and these are the best badminton shoes I've ever used.