I searched high and low for a cushion cover in the right colours to go into my newly refurbished spare room.........(well, honestly, it was really only a perfunctory look) Couldn't find anything, so I bought some wool and knitted my own. This is knitted on the diagonal, so you start with very few stitches at one corner and increase at the beginning of every row and then decrease once you reach the widest point. The reverse is four squares knitted diagonally in the four colours I used on the stripy side.
I love the complementary pep in this room now - you would think such strong colour contrasts would be a bit hectic, but, on the contrary, I find it restful.
Total cost for renovating this room: around $250!