I am on a similar boat as you looking to buy a proper phablet as its great for commuting. I have the Samsung Note 1 for 4 years! and I have my eyes set on the Huawei Mate 8 after I had a look at the 7 back in October. Only problem - for me - is they still haven't released the 4GB Ram version in Europe and the more i wait the more phones come out pff. Plus i refuse to get a new phone with 3gb ram in this day and age when the Note3 had 3gb ram years ago. I want to future proof my self as i tend to keep my phones for quite a lot.
Another contender closer to the size you want would be the LE Eco Max Pro (former Letv) the first that has the 820 snapdragon but again its a chinese phone and don't know if it will ever come officially here. I think it hasn't even released officially yet, only 1000 dev phones have been sold so far.
Oppo R7 Dual - i think - is 6 inches as well and in a week's time they announce the new one oppo R9.
Sony has the C5 Ultra at 6 inches as well but i think not released officially in the UK.
Huawei is announcing the p9 on April and there is rumour that the Max version instead of it being a 6.8inch like last year, its going to be 6.2. Finger's crossed as i think 6.8 was too much, and i love massive phones they are great for the bus, but need to be able to put it in my pocket
. Mind you last year the P8 lite and the normal came officially in UK the max never did so we don't know if Huawei will do the same this year.
Out of the above the mate 8 is a flagship and has the fastest - till now - processor surpassing in user experience the S6 and note5 and there is a youtube comparison video with the s7 that it is on par in most aspects. Mind you the gpu is not as good, but for my usage i have a vita for commuting gaming needs..
The Oppo and C5 are more mid range phone but also the price is a lot cheaper. I think the C5 had issues with the battery though..