guestmount is much too slow for my use case, unfortunately (running it inside VMs). kpartx/mount is much faster. To my knowledge, no project exists that ships scripts for kpartx based mount/unmount. It would be useful to have it abstracted in with some nice /usr/bin/mountraw /path/to/raw /path/to/mount/folder interface. I am not too eager to create such a new project / repository etc. Would you be interested to ship kpartx/mount based (u)mount tools together with libguestfs? I am not an expert, but I might contribute those scripts if you are interested. As separate bash based scripts. Would you be interestd to have them and maintain them?
A key feature of libguestfs is isolation of the host kernel from exploits: http://libguestfs.org/guestfs.3.html#security I don't see how providing scripts would do anything but encourage people to expose their hosts. Also I can't see how these scripts could be made to work, in the presence of common guest features like LVM. If the scripts used libguestfs for inspection, they wouldn't be any faster either. If you have performance problems, look at: http://libguestfs.org/guestfs-performance.1.html