I haven't seen any off the shelf ones but there are some posts by "4shorts" who fabricated a set of front mudflaps for his L5740 - and a number of additional interesting modifications.
Last year my boss called around and found an aftermarket set for our l6060. I think it was at wolf kubota in grand rapids michigan but im not 100% on that. the problem is that they were $900. I think he said they were made of plastic and i dont think he mentioned a brand name. you may have better luck checking the Canadian market. they seem to run them more. I ended up building my own with a 40 dollar trailer fender from tsc a 20 dollar set of flaps from O'riellys and some scrap.