Hello Christoph. It is good to see that the project is active again.
I use CdCat mainly to catalog the several external HDD I possess. The tool is quite complete; however scanning of HDD is painfully slow. I suggest the use of NTFS Master File Table to dramatically increase this.
The first pass scan of a NTFS HDD could be made thru the use of MFT. A second pass will be needed in order to look into zipped files, mp3 tags, and file contents. However, with the usage of MFT table, the first pass and indexing can be performed in mere seconds. If the second pass can be performed in background, I think this would allow for an incredible increase in performance.
The speed of indexing thru MFT is really amazing.
Everything search is a closed source freeware example of this (check http://www.voidtools.com/\)
An open source implementation (which I have not tried) can be found in http://sourceforge.net/projects/ntfs-search/