http://www.refurbups.com-- APC's Smart-UPS line is one of many that does do a pure sine wave output.

Pure Sine Wave UPS Systems for A/V Installations with Drivers Written for AMX and Crestron Chicago, IL (June 8, 2009)–During InfoComm 2009, Tripp Lite will be showcasing its Pure Sine Wave UPS Systems ...

With the increasing popularity of alternate power sources, such as solar and wind, the need for static inverters to convert dc energy stored in batteries to conventional ac form has increased ...

The electrical supply might be inconsistent in your area. But blackouts can’t keep you from going about your day and getting things done, can they? When the electricity goes out in your area, a pure ...