You can find countless phones these days that allow you to connect up to an HD display thanks to MHL or mini HDMI connectors, but the upcoming Galaxy Beam from Samsung acts as its own display thanks to a built-in projector. It's not going to replace a Sim2 or Runco of course, but it beats just about anything out there in terms of portability.
The Galaxy Beam's built in projector can display an image with an nHD resolution which, if you haven't followed smartphone news, is a new term that describes a resolution a ninth the size of full HD. In other words, it's a 360p resolution. The phone, of course, does normal phone things too. It packs a 4-inch display, Android architecture and a thickness of just 12.5mm. There's no specific data on the release yet, but you can expect to see it in the summer of this year.