Actually, I've just been reading
Boyd Morrison's "The Ark", which I'd recommend as being worth a look in that vein.
They're mentioned elsewhere in the Freebies section & the author's recently joined MR, I believe. The books are currently available as Mobi, PDF or online HTML but I understand that ePub versions are due to be added in a few days or so.
[Edit] And are now available there in ePub too...