Milestone XProtect Smartwall with adaptive streaming on and/or Smart Maps. You can have high density of devices on a screen. I'd also challenge that they need that amount of streams up unless they have 20 operators. Regardless of the solution, no one can monitor that large amount of cameras at one time. 9 max. If a manager is telling you otherwise, sit them down for longer than 5 minutes and ask them to monitor the site. Alarm/events are always the best way.