When you do a wipe you're wiping your SD card... so you wouldn't have any data to recover even if you downloaded Titanium again - it stores the backup on the SD card.
Im more lost than you on this i believe. But from what Iv read it stores everything on the SD card. So when you get everything back up you redownload it from the market then it should put everything back. At least thats what i believeIf you wipe wont you also wipe Titanium?