I think you might be out of the hobby league trying to build a machine as durable as you're requirements. 6-10 hours a day is going to require a very robust machine. And MDF is a horrible material to route because the dust clogs up everything.
I would suggest you look for some good used routers or even a new one. Komo, Thermwood, Gerber, all make wood routers. It sounds like you'll be in a production environment so get yourself a production machine, it will pay off in the long run. Also make sure to get an automatic lubrication system.
If you're just starting out a new business you might want to save your money and until you can afford a production machine send your parts to a local cabinet shop.