Dell Computer Corp may borrow from Apple Computer Inc’s imaginative PowerBook design to make up lost ground in the protables market, US PC Week reports: the company has begun showing a 25MHz 80486SX-based notebook that features the same kind of trackball and keyboard layout as Apple’s PowerBook Duo, according to sources who have seen the prototype – one of the pluses of the Powerbooks is that the keyboard is positioned in the middle of the space between the screen and the bottom edge, leaving a flat area where you can rest your wrist; Dell could still cancel delivery of the 4 lbs unit later this year, depending on customer feedback, cautioned sources; the machine, expected to sell for less than $2,000, includes 4Mb memory, 80Mb, 120Mb or 200Mb disk, one PCMCIA slot; an external floppy drive; and a track ball centered in front of the keyboard; it is thought to come from Acer Inc.