I thought I'd try a couple of these self watering seed starter trays available from Lee Valley. Water in the bottom tray is wicked up by a capillary mat that sits under the upper tray that holds the seedlings. This tray is essentially bottomless so the soil in the cells is in contact with the capillary mat which stays wet as long as there is water in the reservoir below. Although they look solid, the trays are made of polystyrene foam (styrofoam) making them unbelievably light and kind of flimsy. And they weren't cheap either. But I needed something and I felt like splurging a little. Maybe I'll switch back to recycled drink boxes next year.
The two trays I have started contain Gold Medal, Black Cherry, Opalka, German Green and Zapotec Tomatoes as well as Ground Cherries and Cape Gooseberries. And I've got a small container of Green Tomatillos started too but I believe those seeds are too old and won't germinate. Maybe I'll start some other old seeds I have, just to see if they're still viable.