Okay folks, here goes nothing.
RomKeeper preview release is up here:
RomKeeper-debug.apk.
What works:
* Download ROM manifest and populate a ROM database.
* Keeps a manifest cache to detect when updates happen.
* Checks for updates in the background, and notifies when available.
* Downloads full ROMs directly.
* Launches a browser for mediafire links to full ROMs and uses the results.
* Applies ROM patches directly without saving to sdcard.
* Launches a browser for mediafire links to patches and uses the results.
* All ROM downloads and patches are verified by file size and digest (md5sum).
What does not work:
* Install launcher probably doesn't work, I wouldn't recommend it.
* ROM verify status is not kept in sync very well.
* UI is pretty bare and ugly.
Note the manifest is fetched from an URL formed by a base plus the device model. The base URL is "http://vmroms.com/~vmstorage/romkeeper" and the model for quattrimus is LG-VM670. The result is "http://vmroms.com/~vmstorage/romkeeper/LG-VM670/manifest.xml", which you should be able to view in your browser if you're so inclined. I hope the IHO roms have this same model but I haven't checked. If not, it will not find the manifest.
The initial manifest contains the latest quattrimus alpha10 release with all three variants. The AOKP ROM has links to both the full download and a patch against AOSP. This means that if you have the AOSP ROM present, it will stream the patch directly to create the AOKP ROM. The patch is roughly half the size of the full ROM.
So, all you adventurous types can download the app, install it, and give it a whirl. Let me know how it works (if it works) and what you think.
Once this passes an initial smoke test with a few users, I'll start a new thread for it and start soliciting the IHO devs for including their ROMs. Initial testing indicate that IHO deltas should be in the 10mb range, which is roughly 1/6 of the typical IHO ROM size.