Seeking manufacturer of a vibrator module. This is the small part
inside of any commercial massage vibrator; roughly the size of an AA
battery. Outside diameter from 0.6" to .025", length from 1" to 3.5". 
It should run on 6-12 volts DC. I have searched extensively for this
part, with not much luck. Most manufacturers make a slightly larger
version of this, approx 1: in diameter. I have contacted the Thomas
Register category editors, and they were not able to find anything.

JinLong Machinery markets a variety of very small vibrator motors, the
smallest of which are on 4mm in diameter, and 12.1mm in length, a
guide to their models can be found on their site:
http://www.vibratormotor.com/guide-table.htm

However, not of their motors seem too operate on voltages as high as
6-12v. Most are rated at a maximum of 2.4v or 4v. You have specified
what you need them for, so I am not sure if a lower voltage it
suitable.

Another site, Global Source, also have a wide range of vibration
motors.
http://www.globalsources.com/GeneralManager?page=Browse&action=GetPoint&point_id=3000000157581&catalog_id=2000000003844&country_filt=&state_filt=&design=clean&language=en
A lot of the products listed there are sourced from the company I
mentioned above, but there are a number of other brands represented
too.

As far as I am aware, most of these vibrator units are simply a motor
with an off centre weight attached. With this in mind I have also
looked for small DC motors, with the thought that the vibrating
weights may be available seperately. Although I have not found any
sites advertising them.

The Maxon Motor company offer a range of small DC motors fitting your
specifications.
http://www.maxonmotorusa.com/products/

Unfortunately, I have not found a product that matches your volage
criteria exactly, but I hope that perhaps something in the range of
micro vibration motors I have found is suitable.

Search Terms:
vibrator motors
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=vibrator+motors&btnG=Google+Search

DC vibrator motors
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=DC+vibrator+motors&btnG=Google+Search

DC motors small
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=DC+motors+small&btnG=Google+Search


If the lower voltage mean that the options I have found are
unsuitable, please feel free to request a clarification and I will
continue, but from your question, it seemed that the size was your
largest issue.

I hope this helps!

Regards,
sycophant-ga

Outstanding research. Only wish this was in place 20 years ago :)

Thanks a lot, sycophant.