Something that also just came to me, instead of having one large sum on money in one wallet. Who says it can't be distributed and broken down in max wallet sizes of $50 or so. $50 is a common number no one should really care too much about. So there goes your concern about being able to see wallet size. If something costs more than $50 group multiple wallets into the transaction.
And how do you plan to realistically manage 200 such wallet's? Realistically you would have a computer somewhere know there key's which introduces the same inherent risk as having that computer manage a single wallet.
If you really want secure storage you print out your private key's and store them in one or more vaults. If your even more paranoid you can encrypt the information such that you need more than one vault to access the data, but have some redundancy so if one storage location floods you don't lose any bit-coins. Which is where these N of M encryption schemes become useful.
The idea is less about losing coin, and more about concealing wallet size from people that don't need to know about how much money is in a bitcoin wallet.
My idea is more along the lines of instead of pulling out a wad of money you're only pulling out $50 at a time.
Me personally, I don't mind the wallet amount being public because for things lie fundraising it keeps people honest.
The multisig vault makes sense for relatively large stash which would take a lot of $50 transactions to brake down into. Also, as you ask your friends to sign off $50 redeeming txs, they'd see how much did you have previously. Not ideal.
In my paper I propose using sequential generation of parameters so you can break down your funds into multiple transactions, but it's only for convenience, your privacy vis-a-vis your friends is still absolute.
If I recall correctly Bitcoin already provides this out of the box: a wallet is already a collection of public/private keypairs (and not a single public address). You could at any point divide your money over an arbitrary amount of addresses that you own(maybe at a small transaction cost). This does not mean people could still try to understand what's really happening by analysing the full graph.
