Thanks to a newly revealed leak, I can now report that the Kobo Aura H2O has an expected ship date of 1 October. Assuming all of these leaks are correct, the Aura H2O will have a retail price of $179, and sport a waterproof 6.8" Carta E-ink screen.
The Aura H2O is an updated version of the Kobo Aura HD, and it was launched in part because the Aura HD showed Kobo that there was a market for a premium device. The Aura HD was expected to add up to only 5% of Kobo's hardware sales, but it actually accounts for a quarter of their device sales.
The Aura H2O has a similar screen size to the older model, but with a slightly lower screen resolution (1430 × 1080) and a newer generation Carta E-ink screen. It's also certified to meet the IP67 standard, which means thee device is dust proof and waterproof to one meter for up to 30 minutes.
The Aura H2O is expected to launch next week. According to the leaked spec sheet , which was subsequently confirmed by the product listing, it will ship with a 1GHz CPU, 4GB internal storage, and a microSD card slot. It will of course also have Wifi, a frontlight, and an infrared touchscreen.
Based on the product images below, I would say that my previous suppositions that the Aura H2O would run Kobo's proprietary software were correct.