Save yourself some hassle if you just get one with VESA mounts and a slab of wood to drill the 4 matching holes in.
Measure to half the width of the tv support piece. Then measure 2 inches out either side of the middle mark. Then measure 4 inches down from those marks.
Basically, the VESA mounts for those size screens *almost* always have the holes 4 inches apart from each other. Measure on your LCD before hand obviously to make sure.
Hope that made sense, tis morning and didn't sleep much......