It must be a provider, where you tell them, what you want the limit to be, and you provide them with a "key phrase" or mechanism, that are not stored in your account, to enable you, to increase or decrease the limit.
So even if the account is compromised, the hacker, cannot increase the limit, without the "key phrase"
This provider, should also, not have control over your private key. ^Grin^
When the account is compromised, you can simply, sweep the remaining coins to another address or cold storage, to protect it. ^Smile^
Yeah, pretty sure Armory has those functions. They're (debatedly) the #1 secure bitcoin wallet out there