What specifically is the property that you seek, that is critical to your purpose, which you believe truly random data will give you, but no pseudo-random implementation possibly can?
In the best case, a well-chosen pseudo-random algorithm might in fact be able to give you data with that property.
And I wouldn't be surprised if in the worst case, seeding a well-chosen pseudo-random algorithm with small amounts of truly random data would be plenty sufficient to do so.
I know you explicitly asked to avoid pseudo-random algorithms, but I frankly doubt that your reason, which you have so far refrained from stating, is well founded. If you are looking to make some kind of exploit truly impossible, then what you seek is likely impossible. In the world of randomness and cryptography and such, the objective is generally to make things obscenely difficult, because most things cannot be proven impossible, and in many cases are actually proven possible, but it doesn't matter due to how astronomically difficult they are.
