I wrote a Perl script to automatically generate a db.xml database for No-Intro ROMs with corresponding No-Intro screenshots.
The result is a database with about 2000 tiles, one for in-game and one for title screenshots. No manual work at all.
It contains tiles for MS, MD and a few GG games. No SCD games and information about year and genre. Please check the readme for instructions and details.
Have fun with Terraonion TV.
PS: I had a couple of issues with CartDBManagerMD. Scanning Roms in a directory with more than 1000 crashes the program. And scanning the root directory does not generate all required games.dbs files. I ended up scanning each individual ROM subdirectory separately. It's also mentioned in the readme.