The problem is that people keep trying to tie this into the metric system, which is more hassle than it is worth. For example the euro is not at all metric, even though it is a new currency that could easily been made metric. So let's call the new unit millibit instead of millibitcoin. Let's have the symbol be the actual mill symbol ₥ instead of the nonsense that is mBTC.
This idea isn't my favorite idea, but it is the idea that will have support:
1 millibit = 1₥, which currently costs about $0.11 on MtGox.
Again, this isn't my favorite idea but it is the idea that will have support. Who is with me? Its time to win.
your idea does have a great deal of support over here:
https://bitcointalksearch.org/topic/m.1627177
i am 100% in support of using XBT (as official) vs BTC (as informal -- and rejected as a valid ISO)
BTC -> would remain 100,000,000 satoshis (called 1 Bit-Coin)
XBT -> would be 100 satoshis (called 1 Eks-Bit)
read the above posts (as well as the supporting arguments) and see if you don't agree
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back to the OP; i totally agree that BTC is a complete turnoff -- as a self-proclaimed bitcoin evangalist its a pain in the ass trying to convince people to cough up >$100 just for 1. i speak from personal experience that a few mBTC to a n00b would be an EASY SELL