What about trying and reporting back to the community? That said, I'd vote YES - I see no reason why it shouldn't work. Just use the ubiquity installer (install.sh) BUT BE CAREFUL with the install location of the GRUB bootloader. By default it gets installed to the MBR of your primary internal hdd. You should be able to select the MBR of the external drive here instead (afaik in step7 - advanced options)Can it be finished by using install.sh?