Seats from Travelcade, Diamond, and Russell will all set you back over $1000 fully configured. Bike Solutions is a little less, but still not cheap.
The $265 for the OEM seat is a non heated version, so if you have heat, it will be more. But if you like your OEM seat, it's the best price you will find.
One thing that most people don't consider is that the OEM seat is also the only one that is waterproof. All of the aftermarket seats, even vinyl ones, are stitched together and have seams. Water will get through the covers and soak the foam if they aren't covered.
If you are happy with how the foam is holding up on your seat, and just need a cover, contact John at Bike Solutions. He has been working on a cover and I have seen the prototype. It's made from Marine grade vinyl and looks really nice.