Right angle IEC power cable

There is a Wattgate part that you use with their regular IEC part to do what you want. I use them on a couple of mono blocks that are a little big for the shelf they sit on to allow them to be pushed back an inch or so. Defiantly a DIY thing. Take Five Audio, RAM Electronics and Parts Express are doing custom cables these days. Maybe give them a call.
http://www.parts-express.com/wattgate-15-ra-right-angle-adapter-black--110-431?utm_source=google&utm_medium=cpc&utm_campaign=pla

Voodoo cables sells adapters of all permutations.

Audience does provide right angle power plug upgrades ($75 for both ends), I ordered some for one of my systems as the space is tight behind the rack. They fits very snug as well as a side effect.

Audioquest has well made right angle IEC adapters in both directions...they work well, and aren't expensive.

Thanks guys for your useful answers.