For those not tempted by Magento 2, Magento 1 has recently had an official PHP 7.2 patch released.
Magento Community (Open Source) 1.9.2.x up to Magento 1.9.3.x
Magento Enterprise (Commerce) 1.14.2.x up to 1.14.3.x
The *.patch files can be applied using either GIT or patch.
PHP7.2 provides a boost over PHP7.1 of up to 13% faster than PHP 7.1, and over 250% faster than PHP5.6 according to Phoronix.
In addition to the improvement in speed PHP7.2 introduces new security features including Libsodium and Argon2 password hashing algorithm.
For those not quite ready to take the leap to Magento 2 the announcement of this official patch is great news.