You mean something like these?
http://www.arcadianlighting.com/mini-pendant-lighting.html

Track / monorail lighting systems are typically low voltage.

The trick is to decide the power source - line voltage vs low voltage, total light desired, then style, ...

The light output is determined by the type of bulb - incandescent/ led / halogen, transparency of the pendant.

davidtay, those are the mini-pendants we are looking for. How does one know that they work with a track system? When I look up track systems, websites never mention pendant lights that are compatible. Do any work as long as the voltage is not too hight?

You may want to look up sites like
http://www.brilliantlighting.com/kits/monorail-lighting-kits.htm
or
http://www.brilliantlighting.com/mfg/track-lighting-pendants.htm
Typically manufacturers like WAC, Prima Lighting will supply both the track and pendants.

Whether they work properly is dependent on
The rated voltage (eg- 120, 12, 24, ...) for the system as both the bulb and wiring for the track and pendants assume a particular voltage.

If you decide on a low voltage system, there is a transformer that has to be purchased as well.

Thanks for the help! Just so you know, I'm looking for a u-shaped track, 8'-6'-8', with three mini-pendants on the first side (over the kitchen counter), some sort of lighting on the second side (over the range and wall cabinets), and track lighting on the third side (for general lighting and a wall of pantry cabinets and refrigerator). If you have any advice about how best to design such a room, please share!

After determining the max budget, I would make sure that the room has ~ 35 lumens per sq foot.
That way, you can be sure that
1. There is enough light in the room in the darkest nights.
2. It provides a crude way of estimating the number of lights required and whether supplemental /alternative lights would be required.

Check out different brands - they will have pendants on their website that will be compatible with their track. WAC, Lightolier, and Bruck and a few that I know. I believe WAC is the lowest priced. Do you need to use pendants? I used Bruck track with track lights and they look great and are a good source of light. Here are pics that may help: