I just wanted to share my experience and hopefully answer any questions people may have about doing this:
I purchased a 1.5TB HDD and external enclosure to increase the backup size of my 500GB TC, and not wanting to start my backups from scratch I tried copying the sparsebundles to the new drive. To my surprise, I was able to switch my TM source disk to the new drive and the backups picked up where they left off! It proceeded to do an incremental backup, and after it was done I went into Time Machine and could see all the backups from the beginning! Now I can use my TC's internal as storage and keep the external for backups. Hope this helps anyone looking to increase the size of their backups without starting fresh...
I purchased a 1.5TB HDD and external enclosure to increase the backup size of my 500GB TC, and not wanting to start my backups from scratch I tried copying the sparsebundles to the new drive. To my surprise, I was able to switch my TM source disk to the new drive and the backups picked up where they left off! It proceeded to do an incremental backup, and after it was done I went into Time Machine and could see all the backups from the beginning! Now I can use my TC's internal as storage and keep the external for backups. Hope this helps anyone looking to increase the size of their backups without starting fresh...