Slashdot shares a new development in optical wireless. The comments on the ISP Review piece are skeptical, hinting that there may be hurdles other than cost to this application competing with radio based wireless. I could not find a link through to any more detail on the research but the remark about dark walls absorbing too much signal has me concerned.
The commenters seem to point out another limitation, that of the need to essentially put optical hardware in each room needing to serve wireless devices. Despite the claims of working around corners, this seems more like an option for new construction to wire a concentrated area rather than doing what WiFi or WiMAX do which is cover small and large areas regardless of construction or infrastructure.