Several members of The Next Web team swear by Sparrow, a great, lightweight email client for OS X that integrates perfectly with multiple Gmail accounts. Now it appears that an iPhone version might not be far away.

Business Insider has published the first picture of the app, and while it’s certainly in the ‘teaser’ category, it shows that an portable version of Sparrow is at least on the way to being reality.

Developer Dominique Leca told BI that the final touches are being put on the back-end and “basic interactions” for users, and various “dresses” (presumably front-end designs) are being tried out. Leca explained, “We need to see if the UI we’ve come up with makes as much sense on the iPhone as we thought when we designed it. Our focus is efficiency.”

It seems that serious testing will beging on the app in around a week from now, although a release isn’t expected for a few months yet.

Still, when it does emerge, it won’t have to go far to beat Google’s brief and disappointing Gmail app launch yesterday, which had plenty of room for improvement.

The image here is the teaser Leca gave Business Insider.

sparrow for iphone 400 Brilliant Mac email app Sparrow heading for the iPhone, first image emerges