There's a perfectly clear and unambiguous way of doing this. Just say how many copies you want, and then the name of the number in plural.
- Zwei Einsen.
- Zwei Zweien.
- Zwei Siebenen.
Moreover, I agree with Pollitzer that Doppelsieben is also clear, unambiguous and shorter.
Thus, e.g. 923333602111088084 could be pronounced
Neun, Zwei, vier Dreien, Sechs, Null, Zwei, drei Einsen, Null, Doppelacht, Null, Acht, Vier.
However, this has the potential of confusing the listener: if the “vier Dreien” isn't spoken too slowly, the listener will parse it as “Vier, Dreien, ...»en«??” Make sure you say the “vier Dreien” quickly enough, almost as it were a single word, so the listener doesn't parse it as a separate “Vier”.
In practice I think I'd actually say viermal die Drei to avoid this misunderstanding. So it would rather sound
Neun, Zwei, viermaldieDrei, Sechs, Null, Zwei, dreimaldieEins, Null, Doppelacht, Null, Acht, Vier.