Here is a specific proposal: Ranked ballots, equal preferences and truncation allowed. Quota is (1/n+1)+ 0.0000001. Equal first preferences are split into fractions of a vote. All candidates with a quota of first preferences are elected, and overflow lower preferences are distributed . The part of the overflow consisting of "exhausted" ballots can just be treated as equal preference for the unmarked candidates and distributed fractionally (This seems correct in principle and saves mucking around with having to change the quota.) After the overflow any candidates who now have a quota are elected. If there are any seats now left vacant,then counting all the votes at full value, of the remaining candidates eliminate the Condorcet loser (using I'm-not-sure-what completion method). Distribute this candidate's preferences and elect any candidate who now has a quota. If any seats are still vacant, repeat, etc.
My second idea is this: Elect the CW (completed however), and then depending on how many seats there are to be filled, fractionally mark down some of the ballots according to their contribution to electing the winner, and taking into account the "wasted" vote. Repeat until the desired number of candidates are elected. The details of exactly which ballots to mark down by exactly how much I haven't yet thought about, but I shouldn't think it is a huge problem.
Chris Benham
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