Been looking for this dvd-rom ltd-165 (16x/48x) and accidentally found it on eBay. It's an OEM version and goes for US$49.95 (shipping not included) The last I check, the seller has 100 available.
Here is the site
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2042797024
6 days left so I will do some last-minute researching before getting it by using the BUY IT NOW option.
Hopefully this will help for those in the US who's been also looking for this particular drive.
After all, final price will be roughly $20 more than LTD-163 and it can also be made region-free also via firmware(ltd-165P).