There are different ways of designing proof-of-stake. Some of the designs do not require collecting large number of signatures. Our design will be made public by the coming Sunday so in due time we welcome the crypto-currency/Bitcoin community to examine our design.
This is correct. The current wiki (
https://en.bitcoin.it/wiki/Proof_of_Stake) lists two designs; one with lots of signatures, the other with no signatures at all.
There are many other potential ways of incorporating stake. It would be nice to hear what Sunny King implemented. Maybe add something to the wiki entry when you make the design 'public'?