The ceiling kind (they are called maidens btw) usually have proper varnished slats and shouldn't stain. (The concertina type are bare wood, absorb the moisture and get mildewed.) Maidens are excellent - as long as you have a high ceiling of course!
There was one here when we moved in - very old one - but we had to get rid of it when we redid the kitchen (no space for it). I have a friend who still has hers (bigger kitchen and 10' ceiling) and it is brilliant.
How high is your ceiling though, yg? Would you have to walk through dangling wet things? If not and you have space then varnishing the slats should do the trick!
Erm, my wooden airer doesn't leave brown marks on teh clothes. Did when I first got it but prob because I got it for £2 in a house clearance shop and suspect previous owner prob died of lung cancer. Just wiped it with diluted bleach. Fine now.