HEAT&GLO offers sum of the most stunning gas and woodfire places for the backyard. There are landscape units and traditional models. They are lighter in weight that can be built around with traditional framing materials to keep the weight down.
MONTIGO outdoor gas fireplaces offer prefab units that are ready to be set on the patio and hooked up to gas and electric. They offer some models with fans to distribute more heat.
AMANTII has a line up of electric fireplaces for the back patio. They offer simple installation with bright flames and light weight.