Three subcommands should be added to siac wallet:

• siac wallet watch [addrs...]: start watching a set of addresses
• siac wallet addunlockconditions [uc]: store a set of unlock conditions in the wallet database
• siac wallet unlockconditions [addr]: look up the unlock conditions for the specified address

These make it a little easier to use the Ledger app with siad. They should all be fairly simple to implement using the client package.