A new study today reveals that nearly a fifth of buyers would like to buy Apple's rumored tablet if and when it ships. Even without knowing its features or price, about 18 percent of ChangeWave's January panel say they're either "likely" (14 percent) or "very likely" (4 percent) to buy the touchscreen hardware. The demand is on par with what was seen when the researchers asked about a then-upcoming Intel Mac in August 2005 and, while very likely to change, potentially hints at substantial pent-up demand.