Question, I've never moved a project from one Raid to another. I just did and when I open the project, all the media is there ready to go except the render files. Is it normal to have to re-render the timelines?
Have you moved your render files to your new Media Drive and relinked the Render files only off those timelines?
If you select the timelines the click Reconnect Files and then in the next window only select renders and offline files it should find most if not all of your assets including the renders. If not, just re-direct the files to where your new drive is at. Works for me when I move project files around.
The best thing to do - and this only really works if you don't have other projects connected to that RAID and you aren't mounting both of your RAIDS on the desktop at once - is to rename your second drive so that it has the same name as the first.
That way FCP doesn't even know you've moved the files, as long as you keep the file structure the same.
If you have to change the name of the drive, reconnecting media clips works well, but I've found reconnecting render clips unreliable. I'd bite the bullet, crack open those 80 sequences, switch autorender on, change the render settings to Render All and leave it going overnight.
My mega timelines are simple talking heads. I have a big corporate client that loves to send out video emails. So, I shoot all their sales guys doing a simple 1 min promo. Then edit them down to WMV and they send them out as video emails. Sure, it's not for the reel, just the meal! And in this economy, I'm lucky to get that much work.