Well, I finished off that 8GB "hacked" card, and once the counter gets to 0 it's done:
The CF card is full.
Replace the CF card.
I got 1467 shots onto that card (Large, Fine, JPG's).
When I view the card properties with Windows Explorer it says:
Free space: 1.89 GB
Capacity: 7.60 GB
I must have done something wrong, because the camera won't let me access the last ~2 GB.
So, I put the card in my camera and formatted it.
Then it said I could take 2086 ISO100, Large, Fine, JPG's (this is the correct amount).
Oh well. I guess I lost ISO3200 and spot metering on my XTi (for now).
I will have to put it back on sometime and see if I can get it to use all 8GB.