If you're still looking for a sturdy scratching post; I'm saving up to buy on of these:

http://www.katzen-deko.de/kratzbaum-holz/index.php

Yes they're crazy expensive, but I've read they're very sturdy and more importantly: it's easy to remove all fabric parts and wash them separately. (They're 100% cotton too.)

Another website with the same principle:

http://shop.petfun.de/en/

Not sure yet what the difference is between the two, but I'm sure I want one. I wish I would have seen this earlier, cause I ended up spending a lot of money on a scratching post (bought in Switzerland) that basically started falling apart after one month.