This is certainly do-able. Take a look at the Gelato project - they actually are able to do whole user-mode device drivers for PCI. You can probably snag some of their kernel->user-mode IRQ notification code for what you want.
http://www.gelato.unsw.edu.au/IA64wiki/UserLevelDrivers -- Stephen Warren, Software Engineer, NVIDIA, Fort Collins, CO swarren at nvidia.com http://www.nvidia.com/ swarren at wwwdotorg.org http://www.wwwdotorg.org/pgp.html
