AppleInsider notes that Apple has quietly discontinued its compact wired keyboard. The keyboard, which has the part number MB869LL/A, has been removed from Apple's online store, yet is still available (presumably, while supplies last) on Amazon for US$46.99.
Apple originally introduced the compact wired keyboard in early 2009 alongside iMac revisions. The wired keyboard was identical to the Apple wireless keyboard with the addition of two USB ports on either side.
For now, it appears that Apple is still selling its wired Apple Keyboard with Numeric Keypad for US$49 in the Apple online store. Apple also offers a compact Apple Wireless Keyboard for US$69 -- the same Bluetooth keyboard ships with existing desktop Mac models.