I have made mayo on a number of occasions. The first time was with a hand whisk and olive oil. It was very thick and it was green and not very useful at the time because of the strong olive oil flavour. I have made it in a blender and it worked, but it wasn't as thick as store bought. I have made it with a stand mixer and it was at least as thick as store bought.
Did you see the video that Powerplantop posted in this thread:
http://www.discusscooking.com/forum...at-recipe-to-use-it-in-82316.html#post1198333? There was also some discussion of Greg's problems trying to make mayo, like wrong shape of immersion blender.
Here's the video:
Easy Mayonnaise / mayonesa - YouTube