Finally a cheaper DVI- SDI converter
http://www.gefen.com/kvm/product.jsp?prod_id=2566
works both way, dvi to sdi and hd-sdi and sdi to dvi...
Addendum:Configuration for a DVI to SDI conversion requires no more than a simple selection on the unit.
As of March 2005 ( i emailed their tech support )- gefen is no longer supporting dvi-sdi conversion.