MeagUpload and Rapidshare both have 'Happy Hours' where you can get premium features for free. The requirements and times are different for each, and I'll summarize them below, but more importantly, do you think you could add the ability to detect and take advantage of them by opening up multiple connections to max out your download speed? And the option to drop the connections through proxies and resume on the default connection would be nice too, save them some bandwidth.

MU Happy Hour:
Weekdays between 9-11 AM UTC (4-6 AM Eastern time)
Requires free account login info to work

RS Happy Hour:
Whenever RS decides they have bandwidth to spare
Not sure about much else, info seems hard to find.