Sorry, but both Troy and Majorkahuna mentioned class action suits in the above thread, so I focused on that aspect of a civil suit.
As far as hiring a private lawyer as a private plaintiff in this cause of action, please be aware that the less likely the matter will be resolved in plaintiff's favor, the less likely an attorney will take the case on a contingency basis. Not only must the facts and the law be in plaintiff's favor, but the extent of damages must be high enough that the expected fee to counsel would be likely.
Think of the preparation involved. Discovery alone would take months, as any attorney would want all relevant documents/emails, etc. involving other eBay customers in similar situations, those whose ads had been accepted, those whose ads had been rejected, etc. eBay's attorneys would likely send WAY more than plaintiff asked for, increasing the time it will take to go through and analyze the docs the court ordered the Defendant to produce.
I'm assuming from Troy's prior posts on this subject that a simple letter from a local attorney will be ineffective, as Troy has posted. Every potential litigant is faced with the same dilemma. How much is it worth to me to proceed? I can assure you that it would be extremely difficult to find a competent attorney or firm to take this case on a contingency basis for a few reasons: eBay would fight to make the judgement applicable only to Troy, not to the general eBay customers in general. Settlement negotiations would make it clear that eBay would not admit fault and any settlement to Troy would remain confidential.
You can see where this is going. Troy may be able to prove damages, but the amount would not be sufficient for a firm to proceed unless the client was paying them on an hourly basis. I would not be surprised to discover that a large firm, with staff, experience, and capabilities of mounting a suit like this would require several hundred thousand dollars to proceed with the discovery process, and that would not include costs of trial.