Did you claim your loss in the liquidation process? If so we should be able to find you on the list of creditors. Soon including the exact amount.
Yes, I've sent the claim a while ago.
Best to take down the side and stop all trades asap, or freeze all trades or whatever - have a message up with link to the forum, email all customers and see if people are want Bitmarket to open again in a few days or weeks.
There is a message on the site - once you log in it really stands out and points to this forums thread. I've also halted all trading, so no one will sell Bitcoins he can't withdraw. Trying to make an offer will also take you to this thread.
I can feel your good gesture and kindly attitude now, however, it is not right to use the fund of the client to do anything without a serious permission from the users. This is a crime if you are running any real world exchange business. In China, there was death penalty case 10 years ago.
I think the best methods here is try to restructure the debt as soon as possible. tell the users exactly how much the black hole is, and change the unit of debt from bitcoin to fiat money. If you owe 20,000 bitcoin, then it's about 260,000 USD. You can sell the site's code for thousands of USD, and give people serious commitment that you owe them such amount of money. You're live in Europe and if you work and save hard enough, it is possible that you can pay them back in 3 years.