I’m trying to create something I want to send to a 3d printer, but I’d like it to be the right size when it comes back. I can’t find anything that will tell me how many “unitless units” the model is in any dimension. Is it really that hard, or am I missing something obvious?
If you press “N”, the properties panel will open showing the location and actual size of the object.
I’m pretty sure 1 Blender Unit(the default) is equivalent to 1 Metre, but if you want it to be in standard units you can go to the Scene panel (between the world and render panels) and change the units of the scene to metric(metres) or imperial(feet).
Hope this helps 
Thanks, Enigma. I’ll try that when I get home. The only instructions I could find told me to go to edit mode and look for the “more mesh” panel, which doesn’t seem to exist in 2.65.
That means you are using very very old info for a very very old version of blender, ignore it or throw it away, that panel has not existed for years and it didn’t tell you about units, how many other things will it tell you that are complete rubbish
For more up to date info see http://cgcookie.com/blender/2013/02/04/modeling-3d-printing-shapeways/