Yes, you can create your own browser. But there are a few things that make Google Chrome a better browser. The rendering engine may open up. But there are a few other things that you need to consider when viewing a browser. This is an abstract browser architecture, Webkit is just a rendering engine.

Watch this blog post and try to understand what the browser browser does and what engines they use.
http://www.html5rocks.com/en/tutorials/internals/howbrowserswork/
There are many Chromium-based browsers such as Rockmelt.
Disclaimer: This is an image from the html5rocks blog.
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