Hi Steve
I too have a Bowser 241, and in fact tonight, have placed my own enquiry into a lamp/light shade, to see if there's anyone out there that maybe willing to sell one on,
Steve there's a guy I've dealt with recently who hand etches globes. I've seen a version of the one your looking for, yeah I know repos are not t
he same. but this guy whose also called Steve dose a nice job, I have his Sinclair Aviation (another project) if your having no luck give this guy a call....Steve Jenson 218-695-3741 and get to e-mail some of his work.
if you know of anyone with a Bowser shade, steer them my way please.
best regards
Nigel from BC Canada