Nige, the system you mention was devised by a company called Avpro. They got as far as doing fit checks/photo shoots with an Apache and a GR7, but as far as I know it didn't get any further.
On the subject of the great work done here by the AAC and the Marines, I think I overheard someone mention the possibility of using the AH like this in an emergency when I was at Middle Wallop just before Christmas. They also briefed us on how they've been using the Apache to put down fire just 10m in front of friendlies out there (story at:
http://www.flightglobal.com/articles...l-by-fire.html)
Much praise and respect, and RIP.