Lighting for single plants or small groups

I read in a TAG article (not sure which issue it was) about a chap who
had evaluated several types of lights including track light style
halogen lights. What he found was that there are many types of lights
which have built-in parabolic reflectors which produce a fairly well
focussed beam of light of very high intensity at a lower cost than
fluorescent lights. These bulbs are available at low cost and with
low power requirements and might be very useful to folks who want
to "include a few plants" in their aquarium without needing to plant
the entire aquarium densely or where most of the aquarium had low
light plants but you wanted to draw attention to a show piece. A
drawback might be that the one place with bright light might be
the one place where algae grew profusely. 

It also might make sense in a _paludarium_ because you could focus 
the light much more accurately on a small patch of _emersed_ plants!