SPDY's framing layer does not need to run over TLS, but for deployment reasons, it almost always does. It's hard to reliably deploy without running encrypted over port 443, because of intermediaries. Note the SPDY whitepaper says: "To make SSL the underlying transport protocol, for better security and compatibility with existing network infrastructure. Although SSL does introduce a latency penalty, we believe that the long-term future of the web depends on a secure network connection. In addition, the use of SSL is necessary to ensure that communication across existing proxies is not broken."
That said, the C++ Flip server in the Chromium repository does support running without SSL, and the Chromium browser can be configured to support this.
PS: There's also an existing node.js implementation, see http://www.chromium.org/spdy.