I took an old cigar humidor (as I don't need it anymore) and lined it with royal blue velvet, and use it to display my mech-mods (sorry, no pics). Sadly, it just sits on the shelf and nobody really ever sees it (including me), so it was a nice project, but in reality, wasted time/money... because I could have sold the humidor to a cigar smoker and not wasted time and money converting it to a "display case" that is never seen.
The rest of my stuff is sitting on a shelf in my office (five 5' adjustable, wall-mounted shelving from Lowes)... mostly just the juices I'm using daily and mods/tanks I use frequently. Everything else I have is boxed up in their original packaging and sitting on another shelf, in case I need them, or want to sell them or pay them forward to a new vaper that needs a helping hand. The shelves are so I could have a place for things like vape gear and office supplies, printer, fax, as well as my model cars and other gadgets... on the wall in my office, rather than in boxes or all over my desk. :D
The 4-5 tanks I use in regular rotation are sitting on a block of wood (with 3/8" holes drilled for the 510 connection to sit into). The block is sanded, stained, routed-edge, and looks decent enough. The mods I use are just sitting next to it. Batteries are in plastic boxes so I can grab them in proper rotation. All of these things are on my desk, in front of my PC monitors for easy access. I also have a Nitecore i2 charger on my desk, and two i4 chargers on the shelf.
It's not much of a "display" per-se, but it's not like I'm making a big presentation for visitors... it's just basic organization for my own needs. 2-3 three-foot shelves store a LOT of stuff...
All of my juice mixing supplies are stored in the mini-fridge in my office, and glassware is on a smaller shelf above the fridge, so I can mix juices as I need