Due imminently, Honeycomb 3.1 will introduce full mouse support and increased editing capabilities. (theregister.co.uk)
Electromagnetic, interactive, AAAA pen provides full mouse capability (left and right click, drag and drop, etc.) when using Mobi View (turningtechnologies.com)
(Sorry PC players — you still get the level editor with full mouse control, but the rest of these are kind of dependent on having that second screen!) (kickstarter.com)