I'm not sure that this is ever going to work.
The fact is that unless your site is very simple indeed (i.e. has very few dynamic parts) and exists on the click->load->static paradigm which really isnt the way any modern site works anymore, you're always going to have some missing pieces/dependencies.
If it's a super simple site you can perhaps just send the html and then add in a <base>
href to the head of the duplicate?
As you know, these days sites are more like applications and your really need the whole site inclusive of all 'moving parts'
other things which might be worth looking at:
- Using ftp functions of PHP/.NET/Java/Ruby etc to fire
template/css/img directories to a new location.
- perhaps looking at the HTML 2 PDF/Canvas tools which are out there and can show a
visual representation of the current state of the site to another
location.