Haggis parcels in filou pastry or something similar, often with a creamy sauce on the side, have been popular in high end restaurants in Edinburgh for years. There is also a kind of haggis, neeps and tatties layer cake approach to serving haggis that works very well.
Haggis would also be an interesting ingredient in a frittata. Any kind of sausage - chorizo, salami, black pudding etc works well with eggs for breakfast and I can't see why haggis wouldn't work too. However, I would echo other posters in saying that haggis is a lot more likely to crumble and would therefore need a binding agent such as egg to maintain the structural integrity of a patty/burger. Note that different haggis recipes have very different textures and flavours. Different levels of spice and oatmeal content will result in more or less successful outcomes depending on what you are trying to do with your haggis.