Unlike its brethren on Windows and UNIX/Linux, it has not been possible to specify the profile directory for Opera on OS X, making it difficult to maintain multiple installations. This is particularly problematic if snapshots are not set to use the correct profile directories (which happens from time to time) or when trying to migrate from a snapshot to a final release. Discussed below are two ways to circumvent these problems.
http://weblog.timaltman.com/archive/2009/02/19/running-multiple-versions-opera-os-x
