Managing 3 iOS devices and thousands of photos. Help!

I have a 5th gen iPod touch, an iPhone 4 and an iPad mini.
Bear with me, I'm trying to explain this as best as I can.

1. Currently, on all three devices, I use wallpaper apps, and for awhile, I used to download the same wallpaper for each device - the apps crop them for the specific device.
2. I also take photos on all three devices, and the photo resolutions are about the same, so they'd work pretty well as wallpaper on all three devices.
3. Right now, the Camera Rolls are managed with Image Capture, from where I send photos from each device to folders named "iPad import", "iPhone import", "iPod import". After I review what I imported (I do touch up/modification with GIMP), I then move them to folders (labeled after the device) for each device and sync the respective folder in iTunes to the matching device.
4. The amount of photos total has amassed to over one thousand, and my problem is that iOS marks each photo in the Camera Roll as "IMG_1234" - I want to combine all photos, sans duplications of any kind, into one syncing folder.
5. I don't want to use iPhoto, I've had some bad luck in the past with it.

I almost want to turn to cloud storage for all of this, but I don't think I can sync that through iTunes, and I'm currently using Photo Stream, but I don't find it to be the best option (as it deletes after 30 days, and holds up to 1,000 photos). I have SkyDrive as well…but that requires the SkyDrive app to access it, and I don't know if you can set the wallpaper from that. (Or sync that through iTunes either). I'm pretty sure Dropbox is the same.

I'm all out of ideas here, other than to tediously wade through the photos, and sort them out. That could take hours, or days.

I'm hoping there's a solution to this that I've missed.