I was reading a recent thread questioning 12v reading lamps and heat generation. I have always liked these gooseneck lamps for reading. It can run on 12v direct or with a 110v adapter. I use one in the house next to the bedside for reading with a variable rotary switch.
I have not built the TD, but will consider using it when I do. Perhaps some new TD builders may find this suggestion useful when selecting a lamp source. I see they have new LED styles as well.
http://www.littlite.com