Hi,
there is a built-in alert which can help you track those files down, it's called Datastore Excessive VM Log Files. It alerts you when there is a datastore with more than 1GB worth of log files. Unfortunately, it can't take you all the way to the VMs with large log files, but if you open the alert, there is a magnifying glass icon next to each datastore which, when clicked, will show you the VMs on the datastore in question.