Yes, something like this. I also found a nice "Bonora" cap, but those are stupidly expensive!
Maybe a self-build?
Yesterday I allmost finished the left hand panel and top.
Here it is roughly cut out and started to shape:
Getting close!
After that I masked the right hand panel using tape:
Peeled off and turned inside out it makes a good but sticky stencil for a mirrored panel:
Excess material marked to be cut:
Here are the three parts for the tank body. At first glance the panels look quite symmetric:
I taped the parts together and they fit quite well. The left side seems a bit more flat to me though. I will need to work on this. But the "tank" makes for a nice slim shape. It's still a bit high in the front, but tihs will be taken care for by the tunnel cutout:
So long,
Andreas