I have and even spoke with them in person at Hay Days!
I highly recommend them!
I am planning on having one made up for an inline 2 place that I want to build!
Once you have gone enclosed you will wonder why you didn't do it sooner!
At the cost of about 200 a cover for your sleds and still have snow and Ice built up on them from the road,
compared to the less wind resistance and clean sleds and be able to toss your gear bags in as well, you will love it regardless of the expence!