The answer to this may be Priorities.

Being able to drag and place the searches in a customizable order, with one side (higher or lower among the list tabs) giving a higher or lower priority to the 'continually updated search/download'. This could mean checking in shorter or longer intervals, or perhaps sending more or less queries for each interval.

But for that to work effectively, there should be a setting in the options signifying what level or difference each search should have over another, if any.

For example: perhaps the number 1 search should be KING and search 50 out of 60 seconds with the second and third searches take just 5 seconds each to round out the minute. (Percentages could work here.) Or perhaps setting them all identical to poll between them equally, or even all identical to waste bandwidth and CPU by running all continually at full power if the user so choses (as long as it doesnt hurt the network).

If a user sets it badly, and negatively affects their own computers ability to function/download, then its their own problem. If they are smart, it can be a powerful tool. The Default would of course be conservative and efficent so no one needs to mess with it to use Limewire.

Thats my 2 cents on the thought.