Came across a great article on plug-and-play modular EHR by David C. Kibbe, MD, MBA, senior advisor to the AAFP’s Center for Health Information Technology. The author questions the push for adoption of comprehensive EHRs when in fact that the needs of a practice (market) might be for some its components such as e-prescribing or a registry function. He proposes a shift from vendor-centric approach to platform-centric one where the practices are able to purchase and adopt EHR "modules" that follow industry standards.
This idea is certainly not new, consider this blog post by John Halamka where he states that Partners Healthcare and Beth Israel Deaconess are using a platform-centric approach for EHR and quality reporting, and are on their way to meet the meaningful use criteria.
Interoperable plug-and-play modules make sense to me. Buy components (modules) you need, connect new components with ones you already have on the platform.