Piecemeal MVPs use existing market tools strung together to simulate the end use of the product. If This Then That , Mailchimp, Google Tools and other automation products can be combined to create a piecemeal experiment. Though an MVP created this way can seem like a good ongoing solution it's important to remember that MVPs built by putting together multiple products can get glitchy so this is a short term test product. Use your piecemeal MVP to learn what you need to understand the user experience and keep moving!
Piecemeal MVPs are great for testing an automated process quickly and easily. They allow you to test and validate tech flows before investing time and effort in building it yourself.
Sometimes building your MVP to look and feel like your final product with technology is the best means of testing your hypothesis. Using existing solutions also allows you to use their back end tools to measure some aspects of the process which can help you inform your own build.
If This Then That, Mailchimp, Google Tools , any website builder