It has been quiet some time now. I just wanted to let you know that I've tried out what you suggested. Here are my results:

Arrays...
for the moment I'll go with them as they really don't affect the performance and 30.000 or so entries are manageable that way. I've tried that on pretty slow machines - it works just fine. I did not experience a decrease in the framrate.
My next variable-intensive project however will definitely not use arrays! It just creates a lot of errors when you insert the right number in the wrong place (and that will happen quiet a bit!). And looking at a huge sheet filled with numbers really doesn't help finding the error.

Textfiles...
do work too. But still, it's everything but comfortable reading a *.txt from a running game. It gets even more fun when you want to save changes made during gameplay.

Structs...
somewhat similar to the arrays. But far easier to keep an overview. Honestly... I made a lot of newbie mistakes trying to use structs. So I'll have to read/practice more with structs before I can really use them I guess.


SQL/GSTlite...
that is why it took me so long to write an answer. I was not familiar with SQL (just knew it was some kind of database). After playing around with SQL I think it is way more powerful than what is needed here.

So thanks for all your help.


By any chance... do you know how the big guys in the industry approach this problem? World of warcraft for example (or any MMORPG for that matter). A couple thousand players each with loads of customizeable stats, hundreds of skills/statistics to save. Etc...