I store all my heavy stuff on 2 moving dollies, and they slide under the lathe. Of course I cover them with cloth to prevent chip migration!
No room under my lathe for anything. But your storage method makes me think. Maybe not as inventive as
@CWret, but ok for this discussion.
How about a similar mill tooling cart with a lower shelf for heavy stuff, a small built in lift boom to raise whichever item is on the lower shelf, and then slip in a slider shelf at the top, set the tool down onto the top slider shelf, then position the cart, then slide the tool over onto the mill table. This would keep the bulk of the weight down where it works best, provide for multiple heavy tools, and keep our backs healthy.
The lathe is another matter. All my current chucks are manageable on their own. Even the big 4 jaw. I mostly keep them on my lathe tool chest which sits behind me while I'm working on the lathe. But I recently bought a BIG 3-Jaw that had been sitting unused for 20 years. I found it quite by accident at a garage sale. It has a D1-6 Backplate. I'll have to install a D1-5 backplate to fit my lathe. But this chuck is HEAVY. I can still lift it, but it's a grunter and why? I think another cart is in order for my lathe. This one could definitely benefit from a small Gibb Crane cuz I can't simply slide a big chuck over onto the lathe - it doesn't work that way. That would also clear up some space on my lathe tool cabinet. But it also raises the specter of it getting off balance so it will take some thinking. Same goes for my anti-fatigue floor mat.