Implement an unmetered ADSL option

I don't even know if this is technially possible but it's a suggestion anyway -

Most of the time I'm happy with A&A's way of billing and metering usage. But sometimes I'd like to
1) Download something large during peak times
2) Leave my computers on without worrying that a large WoW patch or windows patch will decide to download and eat up a large chunk of my usage.

So I'd like to suggest you implemented a way to turn on (and off) unmetered use either on clueless or via a different ADSL login. Although it would be unmetered, I'd of course expect the available data rate to be *heavily* managed from minute to minute and to to have no guarentees on availability or latency and even to be zero at the most peak times. Basically I'd like to be able to say that I'll take a share whatever amount of transfer you have "free" at that moment and in return I won't be metered for it, or metered at a low rate even at peak time. In addition to being useful for me, this would help A&A manage their peak usage and therefore costs too, as I belive their costs depend more on capacity than actual usage.