I wouldn't spend too much on linen and stick to staples like Banana Republic and JCREW online. These are all washable and at BR, they usually have a linen/cotton blend which does not wrinkle as heavily. Also smartbargains.com usually gets some designer ones at a discount. Club Monaco (not online) usually has a nice selection as well.
The whole point in buying linen is that it will wrinkle. RL Polo linen items used to (or still do?) have a tag inside that said something like: "100% linen, guaranteed to wrinkle" and that really the whole point. I don't like J. Crews clothing items, as well I have seen the cotton / linen Banana Republic pants that you are writing about and I did not like them when I saw them at the store. Although, I did see 100% linen pants at BR, but they utilize a drawstring closure; and the drawstrings are way too thick, plus they are a new item, so I don't think I want to spend the $68 on BR pants (theory on the other hand...), maybe when they go on sale. Jon.