You have the dream situation - the ability to create a brand new product from the ground up. You want it to be scalable, performant and easily updatable (since you're building in an incremental fashion). But since you're a start-up, you don't want to deal with the headache and costs of hosting. Well, one possibility is taking advantage of cloud platforms (Windows Azure, for instance) and architecting your system using a CQRS-style pattern. See how you can create a system patterned on CQRS in the cloud. We can take a look at a product I created (BrainCredits) and also see how others would take advantage of Azure services to create CQRS-patterned systems.