There are 24 addresses containing values below 4 mBTC in my wallet. I just ticked all of those addresses, and my Bitcoin-qt shows the total is only about 28 mBTC with the estimated total size of 3630 bytes and fee about of 36 mBTC. So I cannot even use them to buy something worth 10 mBTC.
These scalability problems are going to be solved and so you should be a little patient with bitcoin. It is true that we have many unspent bits siting in wallets all over the world but i think the core devs should find a way for us to be able to move all those coins in the near future.