stsadm -o setproperty -propertyname max-template-document-size -propertyvalue 500000000
(hard limit of 500Mb)
Then to export the site and import it, run the following commands on your intranet
Note: you will need to give full control permissions to whoever is logged in on the intranet server for the site being imported to. What I did was to give full control to that account, then remove the user once the import is completed.
stsadm -o export -url http://intranet/path/to/website -includeusersecurity -nofilecompression -filename C:\somebackupfolder
Create the new site on your intranet.
stsadm -o import -url http://intranet/new/site -includeusersecurity -nofilecompression -filename C:\somebackupfolder