Nope, as far as I know, no one is translating any of the Guin Saga or Moribito novels (and I really, really looked back in the day). The first 5 Guin Saga novels translated by Vertical are SO GOOD though (much better than the anime), but they don't even make it as far as the anime (so frustrating!). I have read some spoilers for Guin Saga which desperately make me want to read more, but also make me very unhappy since it was never finished. Bah.

Earl and Fairy: http://earlandfairy.weebly.com/translations.html
http://kagedreams.livejournal.com/201551.html

Not sure if translating as been abandoned?

The first few Slayers novels were translated by Tokyopop so you might be able to find cheap copies on Amazon/ebay.

I want someone to translate the Allison to Lillia (and sequel series) books, but I don't think it's going to happen.