All eight of mine are stock XF with colour/logo changes to give them their own identity; with
CycleChat being the biggest amongst them @ 2.5M posts.
Having struggled (
or had to pay) to upgrade fully customised themes with other forum software, as well as having them
broken by core updates, I decided that with XF I would limit the changes to CSS styling and very minor template changes so as to minimise the impact as the software evolved (
minimal add-ons too for similar reasons).