There is many Android tablet that is made from China, and some of them come with USB host. Is it possible that using some USB external VGA card to output the result to VGA monitor?
You also need a mini hdmi to standard hdmi adapter and a standard vga cable. Not all devices put out enough power from their hdmi port to power this converter but I can confirm that the Acer Iconica series does. It's likely that other tablets do also but I've heard that phones generally do not.