I'm using the Sharp GP2D12 sensor - 24 of them, multiplexed through a 4051 chip (though I have only hooked up 8 so far). If you decide to go with the Sharp sensors, a capacitor across the sensor power/gnd is critical. It doesn't mention that in the data sheet but I've been digging around and found some helpful info from other users. Also, 10 sensors are going to draw more current than the arduino can provide so you will need to power them separately (with a common ground).
I found the prices here to be the best:http://www.junun.org/MarkIII/
Also - buy the cable. The connectors are hard to find elsewhere.