I work at a small business ~20 people and we're looking for a self hosted solution to our resource planning software. We have a huge variety of job scopes, skillsets, equipment, and technicians. The owners have a hard requirement for self hosting due to the variety of clients we work for who want to know their data stays within our own country.
We also want to integrate it with QuickBooks desktop, make custom invoices (some clients stipulate a specific invoice format just for them), and also making dispatches.
@iocase If you need something simple (inventory, billing, sales) try Dolibarr. If you need something more complete, try something like Tryton (Odoo 8 fork).
I do not reccommend Odoo, as the community version has limitations and you need a subscription un orden to use all the modules.