Is Bitcoin suitable for fast transactions, eg in shops?
The time for when a block has been confirmed is the main issue that seems to arrise. The coffee shop problem (I want my coffee now but this may take 10 minutes to confirm payment)

The mobile reception issue could be resolved by allowing restricted open access with on-site wifi service

There are third party services which may help this very effectively (www.flexcoin.com)

Also SolidCoin offers 3 minute blocks and may be substantially more elegant if a third party service was chosen not to be used for small transactions.