Just my opinion:
I think someone already had the best idea to make sure no one can later claim foul in a raffle drawing and that was, I think, mrtgbnkr's idea to have the numbers be picked by a state lottery that has a pick three type game. Also I believe it was his idea to sell numbers in groups. I would think that would be a great idea so long as the tickets are always sold in sequential blocks of 5. For instance I want to buy into the raffle, I get 5 tickets or 5 numbers for $20. That way there are 200 ticket sets (each set is a block of 5 sequential numbers). Selling 200 ticket sets at $20 each set would be $4,000, which by my guess would be a nice tidy sum. Of course if it seems to much to hope for to sell 200 sets of tickets at $20 per set, then do it for $10 per set.
As for not telling people what number they got - and this is just my opinion - bad idea. This will only allow for someone to later moan and groan that theyy were robbed. Think about what raffle you have ever gone in on where you have not known your numbers in advance of the drawing. None that I have ever bought into. I think sequential ticket blocks (sets) of 5 numbers should be sold, such as 0000 - 0004 (as the first set), 0005 - 0009 (as the next set), 0010 - 0014 (as the next) and so on until all the tickets are sold - or at least until an accpetable minimum amount of them have been sold. (Any minimum amount of ticket sales required to make the raffle go off needs to be announced in advance of any sales.)
As for picking the number, you pick a date by which the raffle will go off, and do so well in advance and announce the date when you advertise the raffle ticket sales. You also pick a state lottery that has a daily pick three lotto type game. The numbers drawn for the pick three by that state on the pre-announced date, are the winning numbers. Just make sure that you are certain that the pick three game is the morning or evening game if you use a game's numbers from a state like New York (which would be sort of Gun Rights justice in my opinion).
So if this raffle had already sold all its tickets, and if yesterday: May 14, 2005 had been the drawing date, you (or anyone in the raffle) could have gone to the OFFICIAL NY Lotto web site, and could have checked the pick three numbers for whichever pick three for that day corresponded to the raffle (mid-day or evening pick three in NY) and there would have been the winning raffle number for anyone to see - and it would have been drawn by a totally independent party from the raffle.
As far as hlding money goes, I think whoever sets up the raffle should hold the money and then send it to the family with best wishes from us all.
Something else to think about is tha as a condition of the raffle you must note in your conditions that anyone who buys a ticket, is by virtue of buying the ticket agreeing to the rules and ascertaining that they are: legally able to own, possess and have transferred to them firearms, that the firearm must be transferred through an FFL holder, that all federal, state and local firearms lawsa and regualtions must be followed and it is the responsibility of the receiver of the firearm to obey such, that any cost regarding FFL transfer fees are the responsibility of the winner (unless you want to take those out of the raffle money). Shipping, insurance and handling should be paid from the raffle money. If for any rason the raffle winner is inelligible to receive this firearm, his/her raffle ticket purchase money will be forfeit and the prize will be awarded to the next set of sequential numbers that was purchased by a person other than the inelligble one. So if Joe blow buys tickets with numbers 000 - 0014 (or three sets of tickets) and he wins but is found inelligble because the NICS check by his FFL holder uncovers he is a convicted felon, he does not get the gun, he loses his money, and the prize is awarded to whoever has tickets in the block 0015-0019.