Swooping in eight years later, but I recently developed a free chengyu website that does almost everything you're looking for — and more. It's called the Laowai's Unofficial Chengyu Guide, and it includes:
- Stories behind the chengyu (where relevant, since not all chengyu have stories)
- Literal and figurative meanings / explanations of how to use the chengyu
- Usage examples
- English equivalents (for example, if a chengyu directly equates with an English expression like "to kill two birds with one stone")
- Chinese equivalents (for example, if there's more than one "spelling" of a chengyu
- The work from which the chengyu originated
- Commentary that helps explain important cultural and historical context for the chengyu
I'm developing the site myself as a way to keep up with my language skills after I got a job unrelated to Chinese, so there are only a couple hundred entries right now, but I'm planning on doing 1,000.
Hope this helps!
Edit: Here's a sample entry:
To pull seedlings [out of the ground] to help them grow
When someone is impatient for something and tries to hurry things along, only to have the results turn out to be the opposite of what they wanted
用这种方法教育下一代无异于拔苗助长 | Yòng zhè zhǒng fāngfǎ jiàoyù xiàyīdài wúyìyú bámiáozhùzhǎng
| To educate the young generation in such a way is no different than pulling up seedlings to help them grow
强制生育则是不可能的，并且就像拔苗助长一样会适得其反 | Qiángzhì shēngyù zé shì bù kěnéng de, bìngqiě jiù xiàng bámiáozhùzhǎng yīyàng huì shìdéqífǎn
| Forcing people to have children is impossible, and it would as counterproductive as pulling up seedlings to help them grow
Haste makes waste
揠苗助长 (yà miáo zhù zhǎng)
This is an HSK chengyu
《孟子》(Mèng Zǐ), a classic Confucian work written by the philosopher of the same name. The work is often known in English as "The Book of Mencius."
A long time ago, there was a farmer who was worried that his rice crops were growing too slowly. He made a point of checking on them every morning, but it never seemed like they'd gotten any taller. When he realized that his neighbors' crops were starting to grow taller than his, he began to truly despair, and he vowed to find a way to move things along more quickly.
One morning, he was struck with a fantastic idea. He rushed down to the fields and started tugging all of the new growth so that their roots sat a little higher in the soil. He worked hard for the entire day, and when night finally started to fall, he returned home and proudly told his family about how he'd helped the sprouts grow.
Immediately, his son looked up in horror. A moment later, he leapt to his feet and hurried out to see the fields. Sure enough, all of the sprouts had withered and died, and the entire crop was lost.