If you want to do something similar to Web Components right now, check out React. React is picking up a lot of steam right now and because it’s being backed by some large companies, it’s likely to mature pretty quickly. It requires a shift in traditional thinking of how components should be built, but once you play with it, you’ll see how powerful it can be. Now that React introduced the concept of using a Virtual DOM to figure out only the required changes in a DOM update, it seems that other libraries are trying to integrate a similar concept. I recently saw a very powerful demo by Henrik Joreteg at BackboneConf where he applies this idea using Backbone and standard templating.
All of these changes to how we render things to the browser pair well with my favorite, JS library Backbone. Backbone gives you a great set of classes for Models/Collections/Router/Events but its Views have always been pretty basic, allowing you to bring in any View technology and swap out easily without affecting any of your other code. With all these great improvements to the View layer, you’ll be able to drop in Web Components or React, and they will integrate with your existing Backbone Models/Collections easily. There are some great mixins that are being developed to make some of the integrations even easier, one of those being the Backbone React Component.