I have been looking also. I simply searched the Inet and came up with several locations that sell over runs for less than retail and if you want to pay big time, there are many that custom make them for you. Try searching, "Flex Steel" and or "RV furniture".
I went to my local RV supplier and they have a few sets of cushions that were overstock and sold for 150 a set. The problem is finding a set that fits yours MH and a color scheme that appeals to you.
I found a set that was close enough to alter but I am afraid that I will not be able to match the fabric when I look for a new Gaucho.