Eh, there are no multiple formats in current use to convert between, no proprietary filesystems involved, and NPS Browser + pkgzip already spits out the proper folder structure to add to ux0 - I don't think there would be a comparable interest* and that's before getting into a pointless argument on the modded wii vs modded vita audience sizes...
* Myself I don't think I've even used one for the Wii - between simple file operations on PC and Configurable USB Loader's features, I had everything I needed covered