Surprising they've developed on 32-bit CentOS 5 when surely most shared CentOS hosting will be on a 64-bit platform (e.g. would be using > 4GB RAM)! One thing I think hosting control panels are missing is the concept of central administration (i.e. one place where all hosting/domain/platfrom info is stored and this is queried from multiple servers, each running a control panel) and migration (e.g. a site might want to move from Linux to Windows or vice versa or you might want to migrate all sites off one server so you can do systems maintainence on that server). I do think that a control panel needs to be available on both Windows and Linux and be "migratable" like I mentioned - a hosting company needs a single hosting database for billing etc. purposes but none of the control panels I've seen ever consider multiple server+control panels talking back to such a DB setup (yes, the DB server would have to have an admin interface too - but it could be run on one of the "client" servers if machines are at a premium).