There is now a Fedora package for libguestfs 1.12. It requires Rawhide or the soon-to-be-branched Fedora 16.
There are two kernel or qemu bugs which prevent us from running the full test suite (723555, 723822), so we’ve only been able to do the “quick check”. So some bits might be broken.
Richard WM Jones 
Hi! Do you have any objections – will this version run on RHEL 6.1?
This package won’t work on RHEL 6.1.
It is possible to compile libguestfs from source on RHEL 6.
Also libguestfs 1.7.17 (really 1.8) is shipped in RHEL 6 and we may rebase to 1.12 in RHEL 6.3.