I bough a plastic foam one on e bay for 20 quid cos a sheep had bitten a chunk out of it ! Repaired it with body filler and pressed rough emery into the srface as it dried to get the texture right . Used bumper black wax to colour it and it was good to go. Until I put the disco up a tree . You can see the a bar in my avatar on the wreck of my ES.
Over the years have picked up a wraparound with lights,£60 and an a bar (steel tube) that had been cut down from a bent wraparound for £30 with the best spotlights I have ever seen bar none thrown in. I think the moral is that if you keep looking and are prepared to do some work on them,they are out there.
If you can find one that has more or less the right vertical dimensions off a jap truck and ideally the right chassis width (not essential) its not a hell of a job to weld in some extra straight tube to extend to the correct width.
That or buy a disco one that has had the ends bent in,cut it down to a a bar and buy some light guards.Also, I have seen plastic foam wraparounds on early D2s that always seem to be broken on the light surrounds.These CAN be fixed.