Hovabators are good for smaller size eggs and are commonly used; however, most people would recommend that you use an external thermostat to control the temps. I have found that they keep generally consistant temps without an external t-stat if it is kept in a room at fairly constant temps and the wafer t-stat inside is not exposed to humidity.

Vermiculite is easy to find. Go around to a few 'gardening/nursery' type places and you can generally buy it in big or small bags.