The official Casio Singapore website is now selling G-Shock watch stands. The GMC-V3ASET set includes two stands for S$18. The stands have an acrylic block pedestal with a G-Shock logo and a C-ring covered with rubber to prevent scratches. The stands are available to Singapore residents and Casio ID members only (registration is free).
Update: The stands are also available in Japan at www.casio.com/jp with a price of 1,650 yen for one pair.