Reviving an old thread here instead of starting a new one. I'm in the same general location as the OP and was wondering if there are any updates to the list, since it's over 3 years old. Also, I've found the following and plan to check them out in person. I would appreciate any feedback or other ideas. I'm especially interested in places near Baltimore and with smaller class sizes. Thanks in advance!
http://www.ellicottcityaikido.com/
http://www.aikidomaryland.com/
http://baltimoreaikido.com/
http://www.aikidimension.com/