Replace/upgrade mirrored server hardware
I think I would first outline something like this before testing it while recording time with a stopwatch.


D-X


get the newProd and newMirror ready (OS + SQL Server + User Account, job, ...)
build scripts for every step (back, restore, mirror, ...)

D-3


add a new IP to oldProd
update DNS with new IP and TTL = 300s (Time To Live)

D, H-2 or H-1 (I assume backup and restore both take 30min)


full backup of oldProd
restore newProd and newMirror

D, H (Downtime)


Stop applications and DB access
Backup logs on oldProd
Restore logs on newProd
Remove new IP from oldProd
Add new IP to newProd
Start applications and DB access

D,  H+something


Build new mirror between newProd and newMirror



Another option for 4. (downtime should be lower)


Break mirror with oldMirror
Backup/Restore logs to newProd
Create new mirror between oldProd and newMirror
Manual failover to newProd
Break new mirror
Create new mirror between newProd and newMirror


I may have forgotten a couple things.