I think a regular white undercabinet fluorescent tube light is fine. (although you may want to use several next to each other, if you have the room. More light is good!!)

If they're hard to find in such short lengths, I wonder if an undercabinet LED would work for you. I think any kind of light is fine, as long as it's bright enough. Being able to aim it at the plant might be a plus. I have used regular fluorescent tubes and had pretty good results.

Jess

Here is a link that might be useful: Home Depot LED

I use a cone type desk lamp with a twist bulb, has the built in reflecter and works great.

I'd buy a 100 watt compact fluoro bulb, day light variety. It will do just fine.

check out the ott-light natural daylight for plants. it is about 20 bucks its a compact screw in flourescent that was engineered by a horticulturist. I use one to grow my basilmint and dill....just buy that go to home depot and for 11 bucks you will get a clamp on light fixture with a aluminum reflective hood and your good to go

here is the website for the above mentioned light
http://www.ott-lite.com/Cms/nls.aspx

Here is a link that might be useful: ott-lite