Back when permissions revisions were thought imminent, there was a flurry of discussion about implementation. The talk has died down somewhat as there has been no sign of actual change on the horizon.
I love the "alias" idea for inventory. Your other idea is very similar to the proposed "wrapper" system. When you get something with a wrapper, you can transfer it to anyone you wish. Or you can also choose to break the wrapper and make modifications or copies of it, but lose the ability to transfer it.
With aliases, the wrapper would only need to be broken if the item needs to be modified or multiple rezed copies are needed. Then you break the wrapper and can no longer transfer it to someone else. For clothing and attachments, most of the copying is just to put them in different "outfit" folders. Aliases could handle that.
There would also need to either be iron-clad wrappers that can not be broken, or the ability to lend objects without transfering "ownership". If lending were implemented, an object would have "creator", "owner", and "possessor". A lent object could not be modified or copied (but aliases could still be made) and could only be transfered back to the lender (or deleted). Allowing modification to lent objects is an open door for abuse in a big way, and we really shouldn't go there. If modification is required, then normal transfer of ownership is the correct way to go.
Lending would allow games to provide scripted attachments that will run on the game's no-script land, because the attachment is still owned by the game creator. They would act as un-breakable wrappers to protect the code inside from tampering or reverse-engineering, which could ruin the game for others.
Adding some sort of built-in time limit to a lent object, as a parameter of the lending process ("lend for 5 days of rez time or until this date"

would allow the much-requested "try before you buy". So you could let people try a shirt for a few minutes, and see how it looks on THEIR avatar... Or test-drive a car for a few hours... Or rent a tuxedo for a weding... Lots of possibilities.
Aliases, for non-copying multiple references in Inventory...
Wrappers, to allow a one-time switch from transfer to copy-mod, for buying-as-gift...
Lending, for special-permission objects in games and for try-before-you-buy...
As my own follow-up comment: Scripts may need special handling in the wrapper case. Just as making a shirt moddable shouldn't make its textures downloadable, making an object moddable shouldn't make the scripts readable. Both textures and scripts can pass through the "analog hole" and bypass any and all protection the system would afford their makers. Animations too, though there isn't any method in place to download them. Those three represent a large investment of time and tallent that can be manipulated with external tools. That makes them vulnerable.