Electrical Engineering Design

I am working with a company that deploys modular gas and chemical operating plants at remote locations. Each modular system has it's own high voltage panel and disconnects. We also have support equipment at the site that has its own electrical demand. In addition, we are looking to design our process to be flexible to run off generator power or grid, or a combination thereof. Expected total load is around 1-2MW (depending on number of modules deployed) with individual modules between 50-150kw draw. Most systems run off 480V, but there will also be a system that runs off 120/240. I am looking for help in finalizing a one-line diagram and specifying key equipment that is compatible with a 3rd party system we are using. This will help us in procuring key equipment that is a fit for our deployment. The first phase of this is for our next project. There is an opportunity to help with this on an ongoing basis, and a preference (not requirement) for the ability to PE stamp the designs.