After reading about miniature gardens on the 'net, I came upon this.LinkI am now in love. Buy 30 seeds here (scroll down a bit).
I looked at the link - ugly plants!
I can't for the world imagine why they choose that picture. That plant looks to have been defoliated by a hornworm. Anyways, yeah micro toms are a neat little determinate variety of tomato, you can sometimes find cellpacks of plants at the box stores and avoid the whole seed starting bit.
BTW unless your desk get at least 6 hours of direct sunlight I'd probably grow them outside (excellent in hydroponic systems).
Yeah, the desk bit isn't really true....
I was thinking more hydroponic systems, like you said, or growing tomatoes in small containers (a 4 inch deep pot, which is the standard size).
Bonzai tomatoes for your micro-greens salad.