If you want stable and inexpensive you may want to look into a wooden surveyors tripod. That is what I use and have used for years. I mounted a Majestic geared head on mine and it holds everything including my 12X20 with no problem. Cost to me was less then $300 US complete.

Majestic geared heads can be had for a fraction of retail on Ebay. I bought the one with the 6 inch platform. The tripods come up as well. I think that bmac and others use these tripods as well.