We've recently installed Juno low voltage xenon linear lighting for under cabinets in a couple of homes, and customers are totally satisfied with the result.
Transformers are located usually in the basement...we install a line voltage wire for the switch to the basement, and install low voltage lines from cabinets to same location. Install transformer in 8X8X6 box, and splice everything there. Switch the line side. Because of voltage drops, we've been using the 24 volt system with 10 watt bulbs.
These lights are expensive, starting at $1000 (installed) for an average kitchen.
Here's a link:
http://www.junolighting.com/Spec%20Sheets/Juno/D3_2_0.pdf
