I am surprised that you report problems with finding eBooks...
I share approx 2,800 ebooks now... Not all at one time as that is crazy, but I do rotate through them in blocks of about 500 being shared at any one time...
At least 1,400 of them are .pdf...
My sharing volume is nothing in comparison to a few out there...
I know one guy sharing over 8,500 eBooks... ALL of them at the same time... HE is VERY hard to grab as far as slots are concerned.
Regarding 'sources' for eBooks, I find that only Gnutella Network and a selection of DC hubs are really worthwhile...
Labelling, in almost all types of files, seems to be becoming worse and worse these days... So, you may want to try other search arguments... Have you tried simply
.pdf ? And then, WAIT... I routinely have returns of over 14,000 .pdf files...
Good idea to filter out: temp, sex, erotic, erotik, wicca, comic, comix, engineering, physics, etc.,etc.
Patience is required, honest... I've had eBooks in pending downloads for over 4 months... Wake up one morning and, "WOW, it's there !" Happens all the time...
Don't give up !
Share the gems you do find !
btw, please do not make any references to specific copyrighted material(s)... 