Mate,
Type in a search in the 80 series section for gas struts for the tail gate, or;
i had a buddy that went into napa and got the gas struts from an old 70's mustang and fabbed up some brackets and it worked. It actually even gave him an extra few inches of opening, but too much work for what it's worth.
so i replaced my own and went with an outfit out of Australia
They go by the name of gas strut guys and here is a link to one item. http://cgi.ebay.ca/Toyota-Landcruis...ryZ10428QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
They are great, and i even told them i wanted more gas inside to compensate for a ladder that i have on my tailgate, and they adjusted accordingly. Shipping took about a week and they were super awesome.
Let me know what you end up doing.
I know toyota genuine parts charges a ton for these anyways.
Cheers,
Steve