I suppose you could get some Sunbrella fabric they make awnings out of to showcase your sewing skills, but a Weber Premium cover for an 18" WSM or kettle are @ $20 online.
Is your ECB modified? There are chit ton of them out there but the one that comes to mind when I see you're just smoking steelies and salmon with it is Randy'sQ ECB mods. You should check it out and evaluate how serious you want to get with it.
As far as modding it for propane? IMO a turkey fryer burner might be overkill, but Cabelas and a couple other brands have some that are charcoal/propane models you might search them out and see how they are setup.
If I were inclined (not) I'd find a Weber Go Anywhere gas grill, remove the burner tube and manifold gauge and use a bulk hose fitting and 5 gallon propane tank instead. I'm guessing you just want to use it as a burner for a smoke box/tray setup? This is just the putzer in me!
Think about making a Drum Smoker....
Lots of diehard smokers in the Seattle area-I'm an old Capitol Hillbilly in suburbia!
Brian - Left Hand Smoke BBQ PNWBA 2010 Team of the Year
BGE's/WSM's/Pellet Pro WSM/BWS Gater/BDS Clones/Cookshack 008/Weber Performer w EZ-Que/Cajun Bandit/Rib-O-Lator Test Pilot/La Caja China/BBQ Guru/Weber 1000 RK Drum Coffee Roaster
Follow Left Hand Smoke on Facebook!http://www.facebook.com/pages/Left-H...462391?sk=wall
KCBS CBJ/PNWBA CBJ www.pnwba.com