Apple and Adobe took the weekend to announce that a fully featured version of Adobe Flash was finally in the works for the iPhone.

Bringing Adobe’s Flash to the iPhone has been an arduous and, at times, intensely political process. Reports from early March of last year revealed that Apple CEO Steve Jobs was dismissive of Flash’s capabilities on what has become the world’s most popular smartphone. The full-fledged desktop version — installed on more than 9 out of every 10 PCs the world over — was deemed “too slow to be useful.” Jobs also claimed that Flash Lite, a lightweight version of the Flash runtime, was “not capable of being used with the Web.”

Though rebuked, Apple’s March 6 unveiling of the iPhone SDK prompted renewed efforts from Adobe in delivering Flash on the iPhone. “We are also committed to bringing the Flash experience to the iPhone and we will work with Apple,” said Adobe CEO Shantanu Narayen. “We’ve evaluated the SDK, we can now start to develop the Flash player ourselves and we think it benefits our joint customers.”

While the investor call with Narayen brimmed with optimism, Adobe delivered clarifications soon thereafter.

“Adobe has evaluated the iPhone SDK and can now start to develop a way to bring Flash Player to the iPhone. However, to bring the full capabilities of Flash to the iPhone Web-browsing experience we do need to work with Apple beyond and above what is available through the SDK and the current license around it.”

The issue has seemed closed for some months until recent comments by Narayen have rekindled the faith. “It’s a hard technical challenge, and that’s part of the reason Apple and Adobe are collaborating,” he said in a Bloomberg interview during the World Economic Forum in Davos, Switzerland. “The ball is in our court. The onus is on us to deliver.”

Just how much progress Adobe has made in retooling Flash 10 for the iPhone is anyone’s guess, but Narayen’s comments may be revealing. If the onus is on Adobe to deliver, it may be that Apple is awaiting a standalone edition of Flash that does not require the deep API integration that Apple has avoided for their product. Alternatively, Apple may still be waiting for the resource-hungry runtime to achieve a performance profile that’s in line with the iPhone’s capabilities.

As mobile Flash installations pass one billion users in 2009, Adobe and Apple apparently remain committed to the iPhone. “It’s a hard technical challenge and that’s part of the reason Apple and Adobe are cooperating to try and get it done as soon as possible,” Narayen says of the predicament. All the while, many wonder if the final solution isn’t hinged on a “missing product in the middle” that Jobs spoke of nearly one year ago.