I actually achieved this once, but lost my documentation and can't remember what I did. However, I would like to be able to edit items in the frontend without popping up a modal window in lightbox or pop-up of any kind. I would prefer to edit inline, as with other Joomla content. 
I'm going to look into how I may have done this already and post a solution for others. If anyone else knows how, please reply and post your solution as well.

Thanks in advance to everyone who's worked on building and customizing K2!!!