On suggestion from @Yann Guidon / YGDES I've scaled the mechanism by 1.1 times. It changes the dimensions by a very small amount (0.6mm over a character) so that I can accommodate 4mm motors for the time being since the 3mm ones are proving hard to find. I shall maintain another copy of this version of the mechanism in another folder.

Using the prize money from the "Anything Goes" round ( YEY!) ive purchased the following motors and eagerly await their arrival:

http://www.aliexpress.com/item/5Pcs-DC2-3V-1500RPM-4mm-Dia-Coreless-Vibrating-Motor-for-Mobile-Phone/32637931060.html

The electronics design will take advantage of the spring leads of the motors to have a "solder-less" connection to the driver board. As mentioned in an earlier post, it driver circuitry will be similar to that used in Flip-Dot displays (Thanks Martin )

I have been requested by @PAUL DSOUZA to make everyone aware that the features mentioned in this Project thus far are covered under a patent application filed at The PatentOffice, Chennai, by him on 05Nov2014 …5559/CHE/2014. If anyone wants to exploit features of this design, they would need to get in touch with Paul or his patent attorneys (Origiin IP Solutions LLP), as rules require that even the Patent Office to be kept informed of activities in regards to patents.

I have also been toying with the idea suggested by @Keith Minsel using cams to drive the pins. After finding some really cool motors on aliexpress (God bless China) Ive made up my mind to make a prototype using a stepper-cam system to lift pins up and down.

I'm considering using either a linear compound cam, on a circular one. I hope people can decipher the drawings above, The prongs are the same cam followers that I have currently on the design, only the motor block would be replaced. Any help with making the decision is appreciated( circular or linear)

The stepper motors: http://www.aliexpress.com/item/hot-salow-price-20pcs-extra-Micro-stepper-motor-DC-Stepping-motor-with-Screw-Dia-3-3mm/2053510670.html?spm=2114.10010108.100009.4.UGX6T0

I guarantee the size would surprise you.