Finally - A DVI to SDI conversion box from Gefen.
This could be the holy grail of sdi and hd-sdi outputs.

Actually they claim it works both ways:

http://www.gefen.com/kvm/product.jsp?prod_id=2566

The ex?tend?it HD-SDI Conversion Box is a sophisticated, cost-effective tool that works both ways, converting high definition from SDI sources to DVI displays and in reverse from DVI sources to SDI displays. This unique attribute provides extreme flexibility and usability for broadcasters operating amongst varied equipment. High quality, high resolution video is maintained, multiple formats (NTSC and PAL) are supported and HDTV resolutions are guaranteed up to 1080i.
SDI devices are connected to the SDI input and DVI devices are connected to the DVI output. When the source, display and the Conversion Box are powered and connected, video signals are converted to the proper format. The Conversion Box is manufactured with a SDI to DVI conversion. Configuration for a DVI to SDI conversion requires no more than a simple selection on the unit.