Okay, people seem to think donations are the best way to go. I agree. I think taxing Poloniex balances or everyone's XCP balances would be disastrous.

I have created a thread on the Counterparty forums for donations: https://forums.counterparty.co/index.php/topic,127.0.html

The total missing is actually about 6100 XCP instead of 7000, as some people had not yet withdrawn and I was able to deduct balances.

Your donations are greatly appreciated, and as soon as the missing XCP is covered, I will open up withdrawals so people can get at their XCP.