May-Wah has a vegan 'salmon,' but I don't know if anyone here has tried it. Pretty good reviews for other May-Wah things. I also don't know if it's fillet style. Might be worth trying? http://www.vegieworld.com/cart/product_pages.asp?id=538
I've tried it. there's also this product, but I haven't tried this one:
The product AC linked to comes sorta tempeh shaped - a ~1" thick rectangle which can be sliced whatever way needed. It's wrapped in nori (as "skin" I guess), and the "meat" part itself is kind of sweet, kind of fishy. But I've never had fish, so... yeah. I used it in sushi, with teriyaki sauce, and grilled.