chances of reregistering are very slim. you should still be able to take the tax loss at year end, but consult with your tax person for the particulars.
technically, you can still trade your shares in a private transaction. practically, that is very difficult. however, in one recently revoked issue the folks are saying that they have been making private transactions. I have strong doubts that they are but you might want to check out the following thread and ask around.
regarding your chances of reregistration, the following link will show all the revoked companies as of late. I am not aware of any that have resumed trading.