I'm looking through POS / accounting / ERP systems right now to update a really old system (at my family business), and most of them suck; Really, really bad.
I think there's an incredible potential for building an open source ERP (community supported with an option to host in the cloud for a monthly fee or paying for professional support) that follows a modern MVC design pattern and has a module system A la Wordpress, Drupal, Joomla, etc (but doesn't suck). A few CodeIgniter CMS frameworks have pulled this off really well: PyroCMS and HeroFramework.
What it looks like to me:
- Multi-lingual, multi-currency
- Customizable forms for each module (so HOW I store entities in my CRM can be customized)
- An abstraction layer for pushing / pulling to and from some of the popular tools for various things such as payment gateways (which I already have code for supporting 8 simultaneously), CRM (ie highrise, salesforce), point of sale, accounting (quickbooks), etc - so if you're already using something for SOME of these pieces you don't have to migrate.
- Easily deployable web services (API mirrors any data in the system, service endpoints can be turned on or off)
There are millions of businesses still running on antiquted platforms, and the leading commercial choices (Sage, Intuit) are pretty bad. Seriously, check out the list: http://en.wikipedia.org/wiki/List_of_ERP_software_packages
This is a couple thousand hour project, but I've got to do it anyway - so anyone who wants to work on it with me would be highly appreciated = )
And yes, open source can mean tons of money.