Amazon sells longer mats. Everyone sells longer mats- once you know which brand/style you want, it's a search away. I've posted this before:

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=72%22+yoga+mat&rh=i%3Aaps%2Ck%3A72%22+yoga+mat

http://jadeyoga.com/collections/yoga-mats/products/harmony-mat

http://jadeyoga.com/collections/yoga-mats/products/fusion-mat

https://www.manduka.com/yoga-mats/pro.html?length_mats=1159

https://www.manduka.com/yoga-mats/eko-mats.html?length_mats=1158

http://www.amazon.com/Extra-Wide-Long-Purple-Pilates/dp/B0042KUL62

yogaformen.com/Yoga-Men-Extra-Natural-Rubber/dp/B0134JBBJW/

http://www.amazon.com/Yoga-Direct-Extra-Long-Black/dp/B00QTCF9H2

Including 80" lengths:

http://jadeyoga.com/collections/yoga-mats/products/harmony-mat-xw

http://jadeyoga.com/collections/yoga-mats/products/xw-fusion