In version python-virtinst-0.400.3-1.el5

Running:

virt-install --connect test:///default --name foo --ram 64 --pxe --nographics --noautoconsole --disk path=virt-install,device=floppy

Results in:

Starting install...
internal error Invalid floppy device name: hda
Domain installation may not have been
 successful.  If it was, you can restart your domain
 by running 'virsh start foo'; otherwise, please
 restart your installation.
ERROR    internal error Invalid floppy device name: hda
Traceback (most recent call last):
  File "./virt-install", line 865, in <module>
    main()
  File "./virt-install", line 763, in main
    start_time, guest.start_install)
  File "./virt-install", line 818, in do_install
    dom = install_func(conscb, progresscb, wait=(not wait))
  File "/mnt/storage.bos/boston/crobinso/sandbox/rhel/python-virtinst/python-virtinst/RHEL-5/virtinst-0.400.3/virtinst/Guest.py", line 541, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/mnt/storage.bos/boston/crobinso/sandbox/rhel/python-virtinst/python-virtinst/RHEL-5/virtinst-0.400.3/virtinst/Guest.py", line 633, in _do_install
    self.domain = self.conn.createLinux(install_xml, 0)
  File "/usr/lib64/python2.5/site-packages/libvirt.py", line 1073, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Invalid floppy device name: hda


This is fixed upstream by commit, and has been there for a couple months now:

http://hg.et.redhat.com/cgi-bin/hg-virt.cgi/applications/virtinst--devel/rev/fd4baa6410d8

Specifying floppy devices is new functionality introduced by the rebase, so this techincally isn't a regression (and by extension the bug hasn't existed in any released version).