There are some nice, opensource and easy ERPs to look into, like Odoo. Although I agree there's not the way to go (at least not pointing such a big customers), I'm sure nobody will complain if modularity brings along with some extra modules, as expenses, project managament (tasks, time tracking) and/or CRM. Something similar to paypanther or pancakeapp (which both they're not claiming to be ERPs)..
It would be first driven community opensource, simple and easy with that amazing features.
Anyway, that's just a dream, and a there's a long way to accomplish, but all big projects start as a dream