The input API is finally flexible enough to handle this, and the "special" session and sdi are troublesome to support, causing memory leaks among other things.
Status update: The "srzip" input file format requires random access to the ZIP archive while applications currently assume strictly sequential access for input files. There is WIP code to prepare local file I/O in input modules but it's not yet in mainline. The libsigrok library as well as applications need adjustment. git://repo.or.cz/libsigrok/gsi.git wip/input-internal-io-v4