- Lucerne uses IFilters, AFAIK there are no IFilters for the popular ebook formats - MOBI, AZW3, EPUB etc.
- Its written in C# which means it uses .NET, which is Windows only ( unless you want to chance your luck with Mono).
- It depends on ItextSharp which is another C#, .NET package
Lucerne's inability to search the major ebook formats, and its dependence on the effectively Windows only .NET framework probably means there's very little chance that the authors of Calibre would provide any support for it in the core product.
BTW Windows Search uses IFilters (that's why MS 'invented' them) - I have 11 installed. But sadly none for the popular ebook formats. If you know where one can get IFilters for EPUB. MOBI etc, then I too would really like to know where
If Lucerne can produce a list of the files that meet the search criteria, then you could push that list into the Import List PI and get it to create a Reading List.
And have a look at the
Recoll Full Text Search Plugin - maybe you could use it as a model for developing your own plugin for Lucerne - Recoll is a Search Tool that runs on Linux and OS/X, it also indexes and searches EPUB files amongst the usual suspects.
On what basis do you make the judgement that using a plugin would be as "ugly as home made sin"
BR