Another heads up:
THX 1138 PAL 1LD LASERDISC TARTAN TVL 002 is up on eBay:
http://www.ebay.com/itm/THX-1138-PAL-1LD-GOLD-LASERDISC-TARTAN-TVL-002-/131072256545
This is the last LD to be released, and it's listed as being 83 minutes long:
http://www.lddb.com/laserdisc/29697/TVL-002/THX-1138-%281971%29