The European Spallation Source (ESS) will be constructed by a number of geographically dispersed partner institutions in an international collaboration [1]. This increases organizational risk, as control system integration will be performed by a large number of quasi-independent teams. Significant effort will be put into standardization of hardware, software, and development procedures early in the project. The ESS will use EPICS, and will build on the positive distributed development experiences of SNS [2] and ITER [3-5]. The basic unit of standardization is called the Control Box. This consists of one or more input/output controller (IOC) computers, zero or more I/O modules, PLC subsystems, and intelligent special-purpose controllers, and includes software and integrated development environment support. We present the challenges faced by Control Box plans for ESS, and expected benefits.