One-way gateways do exist
There are a few 'one-way gateways' availbe in the market today. You will break a few things if you decide to allow traffic flowing only one way. The most important are: Handshaking, flow control and error correction. You can circumvent this by buffering the traffic, sending it via a oneway protocol (ie udp) via a steady pace (to fix the flow control issue) and add some additional error correction (like with PAR files). You can read more on this here: http://en.wikipedia.org/wiki/Unidirectional_network. <shameless plug>If you like you can view an animation on this here: http://www.youtube.com/watch?v=vemwnQmnvuo</plug>
Biting the hand that feeds IT
