Hello. I experienced a drop for one of my websites a few months back (not Panda related) and I was so puzzled as to why this was. The website has not yet returned to its original position but the other day I found out that the website in question has a number of links hidden using CSS in the TLN. The reason was that a developer thought he'd include 'SEO links' to help with organic search - without understanding the negative impact this can have. The links are yet to be removed as I have to put them through a development cycle (should be next week), however I wanted to know if anyone else had experience with this type of problem or recovered from a penalty that was a result of hidden links?
Do a full site review before the reinclusion request. If this was done without your knowledge there is a good chance some other shortcuts were taken. You probably want to clean it up before you ask a Google employee to manually inspect your site. I know of too many site owners that submitted a reinclusion request which resulted in Google discovering even more infractions.