When I sat down with Omni CEO Ken Case Friday at Moscone West, he expressed the hope that OmniOutliner for iPad would be out by mid-year, but he wasn’t willing to give a concrete date. Case is hopeful that the company is on the right track with development, but moving a Mac app to the iPad and getting the interface right is tricky stuff, and Omni Group seems more concerned about getting the app right than getting it out the door as quick as it can.

Case showed a development version of the App, which the company also demonstrated on the Macworld 2011 show floor on Saturday. It’s recognizably OmniOutliner, though there are some big differences caused by the very different way a user interacts with the iPad versus a Mac. Hierarchical expand/collapse triangles, for example, don’t indent based on the level of your outline. Instead, they sit on the left edge of the screen so your fingers or thumb can reach them without stretching too far.

The content itself remains indented, of course, and OmniOutliner for iPad will also support user-configurable styles for all the levels of a document, though Case said the often-complex style system of will be streamlined in the iPad version.

Due to the limited screen space on an iPad, the app will provide a quick way to toggle columns on and off. If you still have a wide document, you’ll be able to scroll left and right—but the first column of the outline will remain frozen on screen, making it harder to lose your place.

While many iPad apps edit only plain text, Omni Group has built its own rich-text editor, so OmniOutliner users will be able to style the text in their documents. To speed data entry, OmniOutliner for iPad adds a small strip of icons right above the standard iPad keyboard; items in the strip will include options to quickly style text as well as tools to quickly navigate between items in the outline.