To address your "concern" about the profitability of this product, this is a very obvious niche market targeted at the wallets of parents in attempts to improve their child's handwriting and spelling between the Christmas/birthday delivery of the newest iPads, iPhones and laptops take over their brains with auto correct.
I'm sorry, I wasn't aware I was supposed to research all viable producers of digital pens for you. My mistake, here you go:
http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Delectronics&field-keywords=digital+pen . Many of the options here are pens for tablets, but as you can see, there are many actual digital pens being sold here as well. Please do purchase and write at least 250 words review on the various implementations of the techniques to capture your handwriting. Also, create and build a post production prototype of your laughably inelegant glove contraption to monitor user's writing and compare this to the already established non-restrictive methods in capturing user's writing. Personally, I can attest that the accuracy of these devices to be very high.
Which brings us to the fact that the perpetuation of smart devices throughout society today and a laptop in every student's bag has seen the decline in this market from a lack of interest. This doesn't mean the technology has gotten more expensive or harder to manufacture. Just that it would mean that the profit margin and feature sets for each pen would need to be balanced to make this a viable competitor to capture sales from the market. Before you comment on this, please do enlighten us
exactly how much each costs in materials and production before any markups or profits.