[Captivate Android Development] SweetwaterBurns:
I've been meaning to type this up for a while, but this is what I do to alleviate the datadata issue and reclaim some space that otherwise sits unused on data after I move apps. Kind of kludgy and there is a risk of losing your data if you're not careful.

Step 1: Move whatever apps you can to the SD card. I use Titanium Backup as this seems to move more off of datadata than the built in application management. Anything that you need to start at boot or use widgets from needs to be stored on the internal memory.

Step 2: Once you have everything moved, open Terminal emulator and type 'df -h' and note how much space you're using for what you have in /data.

Step 3: Backup your apps to the SD. 2 ways here. Either use Titanium Backup or just a Nandroid backup. I use both, because redundancy never hurts.

Titanium is pretty self explanatory, but even if you recently made a backup you need to make a new one after moving apps. TiBu stores information about where the app was installed(SD or Internal) and if you enable it under Preferences - 'Restore backups to...' before you restore, you won't have to go through the long complicated process of installing a few apps and then moving them to external so you can install more.

To perform a Nandroid, reboot into recovery and choose 'backup and restore' follow the prompts and let it do it's thing,

Step 4: This is probably the most important step. While in recovery, plug your phone into a computer, go to 'Mounts and Storage' and choose 'Mount USB Storage.' Copy anything you don't want to lose over to your computer... in particular your backups. Forget to copy those and you're hosed.

Step 5: You backed everything up somewhere other than your phone, right? Now the fun part.

Go to the 'advanced' menu in recovery and choose 'Partition SD card.' (Because of the way the devices are set up in CM7, the SD card is your internal storage and not your external one) Choose the capacity that will let you fit your stuff(from step 2). I've run with as little as 256, but had some issues with installing apps due to lack of space, so I recommend at least 512. Choose 0 for swap size(We don't need it and as far as I can tell, swapon doesn't work with our phones.)

Step 6: Go back to mounts and storage and mount as USB storage again. Copy everything back to your phone. You should notice that the drive is listed as 16 or 15 GB instead of 14 as usual. This gives you more space for installing apps to the SD and keeping datadata clean and is the whole point of this exercise.

Step 7: if you are going to use TiBu(potentially more space on datadata), do a factory reset reboot and restore(make sure you set it up to restore back to saved location)

If you made a Nandroid, choose 'backup and restore' then 'advanced restore' and restore data. If you partitioned everything with enough space, you should have no issues.

More of a way to workaround wasted space, but I've been running this way for over a month now with no issues as long as I remember to move apps after installing them. Keeping the bare minimum on data helps insure you have plenty of datadata when you need it.

One thing to remember, if you ever decide to go back to stock with Odin or Heimdal, you will lose whatever is on the phone because they repartition. Backup everything you need (which you should do anyway) and you'll be fine.

Hope this helps someone out.