Hey, I'm nothing if not impractical... :D
I suspect we're looking at the "block" in "blockchain" here with that limitation.
Some of the historical records I've uncovered (i.e. old Steemit posts on the subject) talk of a one megabyte limit...
So 64K may be a front-end limitation. However, just as disks are sliced into sectors and blocks, this should not be a limit to a front end programmer dealing directly with the chain.
I'm trying to do multiple things here, probably all mutually incompatible. If I ever get a round 'tuit and teach myself some Steemit programming, I will try to write an app that runs on a local computer and can store and retrieve "stuff" of any type on the Steemit blockchain. In the meanwhile, I wanted to see if "Joe Average" could do it, even on a limited basis. ;)