They have an direct DVI-BNC cable but this is only 1 foot long.
Back then you could choose the length of this. Seems this is the only option now.
http://www.bluejeanscable.com/store/dvi-cables/index.htm
DVI to 5 Female BNC Breakout Adapter, 1 foot
You can also choose how long you want the VGA-BNC up to 15 foot max. but you need an adapter for this.
http://www.bluejeanscable.com/store/rgbhv/index.htm
Belden 1522A HD15 to 3 or 5 RCA or BNC Cables
Back then you could choose the length of this. Seems this is the only option now.
http://www.bluejeanscable.com/store/dvi-cables/index.htm
DVI to 5 Female BNC Breakout Adapter, 1 foot
You can also choose how long you want the VGA-BNC up to 15 foot max. but you need an adapter for this.
http://www.bluejeanscable.com/store/rgbhv/index.htm
Belden 1522A HD15 to 3 or 5 RCA or BNC Cables