I found the following in regards to determining excess contributions and withdrawing.
Basically, I think, if you withdraw the contribution before the tax due date, it is not considered contributed. This only applies if you also withdraw the earnings made on that contribution, which would only apply if the account made earnings using the contribution. Most likely, if the balance ever drops below that contribution amount, then any earnings from that date on are counted toward that contribution, and will need to be withdrawn with it for that year... Ow my head.
But since it's not counted, you could then turn around and contribute for 2013 so long as its before the filing deadline.
http://www.irs.gov/publications/p590/ch02.htmlWithdrawal of excess contributions. For purposes of determining excess contributions, any contribution that is withdrawn on or before the due date (including extensions) for filing your tax return for the year is treated as an amount not contributed. This treatment only applies if any earnings on the contributions are also withdrawn. The earnings are considered earned and received in the year the excess contribution was made.
Withdrawals of contributions by due date. If you withdraw contributions (including any net earnings on the contributions) by the due date of your return for the year in which you made the contribution, the contributions are treated as if you never made them. If you have an extension of time to file your return, you can withdraw the contributions and earnings by the extended due date. The withdrawal of contributions is tax free, but you must include the earnings on the contributions in income for the year in which you made the contributions.