So after some more digging through dusty cdrs I realise that the themes load fine without any hacking. The problem was that I was using the themes from 8.2. I have Gizmo from 8.5b6 but I don't have Hi-Tech and can't seem to find it anywhere either. Does anyone have a copy of it lying around? The sound sets would be great too (I'm missing the Gizmo one).

FOUND EM!

http://blog.kteck.ca/2008/08/30/mac-os-82d8-beta-themes/

They're 8.5b6 and not 8.2d8. Work a treat!