Massive archive restore to Exchange (original mailbox) approach

Hi,

For a large customer I'm in need of an approach to perform a mass restore to mailbox.

Scale is over 10.000 users with about 22 TByte of archived data. Past experience using the Export wizard in the VAC for PST exports showed a long time to perform this task (we use SEV 10 latest Service pack). Does anyone have experience "speeding up" this progress by for instance:

- Adding more "processing power" (servers) to do the restore

- Use other (own / 3rd party) tools that can perform this on higher speed

- other ways.

The customer took years to archive the data into SEV, but "expects" that it can be restored in a blink of an eye.

Thanks for your replies