http://cointext.com/fincen-hearing-requested-for-bitcoin-mining-clarification/
I have to agree with MSantori here. This looks like it was written by someone without a clear understanding of the legal issues involved.
First of all, you can not request an administrative ruling on an issue that is the subject of an enforcement action or court case. If you believe that the facts of your case are similar enough to Liberty Reserve that you would be affected by a ruling in that case, then you would need to make that argument to the court.
It really is not at all clear what you are requesting from FinCEN. You bring up the issue of reversibility of payments. Reversibility of payments is possible under the Electronic Funds Transfer Act. The definition of electronic funds transfer under this act refers to "ordering, instructing, or authorizing a financial institution to debit or credit a consumer's account". I am not aware of any claim that bitcoin falls within this definition (and it pretty clearly does not). The statement regarding Liberty Reserve indicates that FInCEN director Calvery thinks irrevocable payments are a bad idea, and this is used to bolster the argument that LR is laundering money, but nowhere does it state that irrevocable payments are per se illegal.
I would strongly suggest that you retain legal counsel and withdraw this request or amend it to address the specific factual circumstances that you are concerned about. Your request in its current form is likely to be dismissed, and this will simply make it more difficult for you to get the answers that you seek.