Assignment planning

I work for a medium practice, typical assignments range from 2 days for one person to 2 weeks for 3 people. Presently,we use a Lotus spreadsheet for staff scheduling, but I have often wondered if there is a bespoke product, perhaps with the "intelligence" to re-schedule the planner (subject to human override of course) to account for client cancellations, staff sickness etc, by reallocating people based on their grade, qualifications etc. I have seen a few off the shelf products but these seem to be aimed at the "bus-driver" type of schedules.

Are there any products out there aimed at the accounting practice market? Any suggestions would be gratefully received.

Paul Bowden