GPS route optimizer

My type-A personality never lets me stop trying to optimize everything in my life. Recently, Ive started taking data on my commute to work: time of departure and time of arrival versus a number of different routes. This is endlessly amusing to houseguests, and a point of constant annoyance to Christy (who typically records the data while I drive; I record it myself when I bike to work). The result of all this data would be a 2-D color map that could give me an estimate of the shortest route depending on the time I was leaving. However, on further thought, I realized such a chart would only tell me about routes I already knew and would be very sensitive to my route ordering. For example, if there are three ways to get to work, how do I order them? By length? By number of turns? By my perceived annoyance of that particular route? I then got to thinking of taking time measurements between each possible node in a route. Those segments could then be built into routes Ive never explored before. You can just imagine the look Christy gave me when I suggested this. Clearly, this is best done by a computer. So the question: has anyone seen anything like this, or a GPS unit hackable enough to permit this without carrying a laptop as well (Id like to do this on bike, too)? Wouldnt the final version of this be sweet?! You tell it where youre going, and based on past experience, the time of day, and real-time traffic data it suggests the optimal route. (Ive seen GPS + real-time traffic, but my guess is that traffic data isnt nearly as useful as past experience data.) To everyone that can relax while commuting and not worry about 16 versus 17 minutes: I envy you.