External HD for MP Leopard backup Boot

On my old G4 Mac, my BU strategy on 10.4 was to periodically use Superduper to clone my inernal HDs on to a FW800 external drive in order to have a "fast", convenient bootable backup. This was for security as well as in case something went wrong on my internal boot or I wanted to try something on the internal that could quickly be reversed by cloning back to my internals (this has "saved my bacon" many times).

Now that I'm getting a new MP and while planning to use a separate internal 1TB for Time Machine, I would still like to also use an normally disconnected external FW or Sata HD for the additional security, convenience and piece of mind of a safety boot from which to recover.

My questions are these:

1. Can my FW800 HD be a Leopard boot drive on a MP w/Leopard once properly formatted and cloned from the new int MP HD?

2. Are there any inexpensive single SATA external enclosures available that can act as a Leopard SATA boot drive (as an alternative to FW)?

3. If yes to #2, are there any SATA PCI-e cards available yet that can host an external SATA as a Leopard boot drive?

4. (sort of an ancillary question) Can I use my old FW800 Ext HD with Tiger cloned from my G4 and mount on the MP as a source for Migration Assistant upon MP initial setup? (Based on other posts, I would probably not use Migration Assistant, but as others have previously suggested, start clean w/Leopard and copy over files, i.e. mail folder, music, browser files, etc, once I set up new users - apparently more work but less chance for headaches).

I've searched but apparently not too well as I can't seem to find definitive answers. Thanks in advance for any help.

 

Can anyone help with these questions?