It's basically a dead-end product now that Pebble has been acquired/cannibalized by Fitbit, but mine does exactly what you want: it wakes me by vibrating on my wrist, and uses a smart alarm to calculate my sleep cycle and avoid deep sleep alarms if possible. Coupled with the week-long battery life, this has made my mornings a lot nicer.
I wonder if Apple is withholding a smart alarm app as a sort of carrot for future models.
I'm actually really worried about my pebble breaking, so have been looking into making a homebrew smartwatch. My biggest issue right now is finding a screen with similar specs to the Pebble Time in terms of resolution and power usage.
If anyone has any advice on how I could get wearable screens like JDI[0] has (without having to buy 100 of them) I'd love to hear it! I'm not super well versed in electronics procurement
Also, for a one-off screen have you looked at contacting a manufacturer on something like Alibaba? They are usually more than willing to send a discounted/free one-off sample of a product.
I looked at a pebble teardown, and saw that it didn't seem to involve very complex production strategies. From that I decided to try building a list of components! I know how to do some microcontroller programming so wasn't too worried about that part, but felt like getting an efficient screen was important.
I've had a hard time finding power efficient screens that I can purchase in very small quantites so I've been stuck there. I've been trawling around parts websites but I almost always end up on things like screens for RasPis.
EDIT: Got some luck on Alibaba searching for "sunlight readable". Going to contact some suppliers to see if I can get something
Maybe the new Fitbit/Pebble Chimera will release something as good as the Pebble some day.