You'll also look a bit of a tool if you get a MB with a buggy bag o' bolts in 10.5.0 and no way back, instead of a nice stable 10.4.10, woncha?
might it be possible, in that case, to use the install discs that came with the original MB to reinstall tiger? (or will they make sure that i have returned them with the old MB) in which case i do have dmg's .