I know if you are looking for out of production racquets like the liquidmetals you have to ask around. I always email and ask if they still have a certain racquet in their warehouse and what they would be willing to sell it to me for. Sometimes you can still find older stuff at their warehouse and they give it to you for pretty low cost.

tennis warehouse – URL
if you are in Australia – URL

But you should know that Liquid Metal is not a tennis racquet, but a series of tennis racquets… ranging from the power in control of the flexible radical
to the spin and control of the stiff prestige