Any Windows 8 (or RT) tablet with full-size USB that can power portable HDD?

I notice a lot of the tablets based on RT or Atom cannot power portable 2.5" USB HDD. I have a lot of those 2.5" portable HDD with USB 2.0 that I would like to plug directly into the tablet. Unfortunately, I think the ThinkPad Tablet 2 cannot power a portable HDD from its USB port.

I do know that all of my laptops (2-5 years old) can easily power all of my portable 2.5" USB HDD.

Does anyone know one that can power these HDD?