It is difficult to vote for a top 50 when all the alternatives are not yet known. We may have to start withdrawing votes if interesting proposals such as
Xeres' proposal
Diolkos are suggested late in the process.
Is it perhaps an idea to go through a nomination and discussion stage and at an agreed point each user send in a ballot containing his or hers top 50? This method will also enable the list to be ordered correctly.
We can can pander to our bureaucratic tendencies by demanding that each suggestion have a formal nomination at the start of its thread.