2 Random Letters Before Order Number Hack Please?

[Brent2]

I am hoping someone can help me with a bit of code. I am only a good "cut and paster".
Here is my story:
I sell a digital product that I think might become quite a good seller. Currently though, it is still in the beginning stages and I have sold only a small number, say "65" downloads.
I know that I can change the order numbers to start at a higher one, say "650", but I do not wish to do that.
My potential future competition would only be encouraged by seeing a higher order number.
Also, my customers viewing the actual order number (say 65) might not have as much confidence in my product or my business if they see their order is only number 65.
Here is what I wish for:
That a randomly generated 2 letter combination is inserted before their order number.
So for example, if the random letters are "ZN", then the order number would be "ZN65".
This makes the order number look very unique, and the customer cannot easily determine that theirs is only order number 65, because it could have gone all the way thru the alphebet before reaching order number "ZN65".
But I would still know their order number is actually just "65". The letter code doesn't mean anything.
This 2 letter prefix before the order number does not have to be added to the admin customer info, unless who ever is reading this and wishes to write some code wishes it to. The order number with the 2 letter prefix could just be in the order confirmation emails that myself and the customer receives.
When I contact a customer, I can always just say to them "your order ending in the numbers ____".
Does anyone wish to take on this task?
I think it would be very cool.
Many companies have similar letter and number combinations.
I think having the actual order number is a bit too revealing.
I greatly look forward to any thoughts, ideas, and contributions from this community.
Brent
PS. zen-cart is great!