I have never seen an actual maximum number of Locale Installers listed anywhere, although I think (personally) that future upgrade/migration's would become very cumbersome if too many were installed.But could be managed with proper planning.
Here is a excerpt from the installation notes for Locale Installer on CCM 4.1.2 (the latest I could find);
Note The Cisco Media Convergence Server (MCS) or Cisco-approved, customer-provided server can support multiple locales. Installing multiple locale installers ensures that the user can choose from a multitude of locales.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.