Japanese Arisawa Mfg. Co. offers a single lens wearable video and TV glasses solution.

The Arisawa Teleglass attaches to apparently any eyeglasses. The lens mount only weighs 8g. The display consists of 0.24 inch LCD panel and a lens which generates a virtual image of 21 inch in size viewed from a meter away.
Last year we reported about a similar HMD developed by Japanese Scalar Corp. Arisawa sells the Teleglass for about 50,000 yen (~$429) and goes on sale in Japan still this year. Arisawa plans to release a version with integrated TV tuner in 2007.
More details on the Arisawa site (Japanese). Via Nikkei.Net (Subscription).