Another palace located in Diriyah’s Turaif district, which was inscribed as a UNESCO World Heritage Site in 2010 and is currently under renovation, although this particular section doesn't appear to be yet. The extensive project is expected to be completed this year.
‘At-Turaif District in ad-Dir'iyah’
“The At-Turaif District in ad-Dir'iyah was the first capital of the Saudi Dynasty, in the heart of the Arabian Peninsula, north-west of Riyadh. Founded in the 15th century, it bears witness to the Najdi architectural style, which is specific to the centre of the Arabian Peninsula. In the 18th and the early 19th century, its regional political and religious role increased, and the citadel of at-Turaif became the centre of the temporal power of the House of Saud and the spread of the Islamic reform movement in Arabia, Wahhabism. The property includes the remains of many palaces and an urban ensemble built on the edge of the ad-Dir'iyah oasis." (UNESCO World Heritage List http://whc.unesco.org/en/list/1329 -- in their gallery are a number of images of the old palaces on the site that aren’t accessible to the public at present.)