[Mr Modifier]

eBay has very inexpensive pre-wired LEDs in various colours (go warm white for vintage look or bright site for modern track lighting).

They are pre-wired for 12v and come in 3mm and 5mm diameter.  Just make sure the wires are long enough to pass down your lighting pole.

Wired in parallel they can be connected to a power bus under your track board and the low current draw means you can run 20-30 off a cheap 1A 12v power supply.