Imagine an Apple iPhone 6 'Phablet'

An Apple 'phablet' could be one of the better Apple products to come along in a while. Screen capture/Brooke Crothers

A 5.5-inch Apple phone would be the device I have the highest hopes for. And it would plug a hole in Apple's lineup.

Of all the rumored Apple products due later this year, the large 5.5-inch device is the one that's got my full attention.

Earlier this week, a research note from Ming Chi-Kuo, a reputable analyst from KGI Securities, indicated that a 5.5-inch phablet may be the pinnacle of Apple's newest phone offerings.

He isn't the first to cite the device. NPD DisplaySearch (among others) back in January said it was seeing activity among the chain of display suppliers that Apple was testing a 5.5-inch product.

But Kuo is one of the first to anticipate some other potentially intriguing high-end aspects.

He believes that the 5.5-incher will get a sapphire screen cover, while other lower-end iPhone offerings may not. And it may also pack a relatively large battery -- "50% to 70% more watt-hours" than the 5S.