Aguille alpine are nice company to deal with if you can get to their shop in Staveley. For a little extra you can customise. If you're taller then perhaps a longer back length. Pick your fabrics, colour , etc. I added length, changed fabrics to a lighter weight fabric on low wear panels and a few other details. Extra cost? Well they charged the cost equivalent to halfway between two standard models. One bigger, one smaller. That effectively didn't add much for the custom features. I think it carried about 60 litres but weight was almost 1kg. Stable carry and could cope with a lot of weight, which I never tested because I was trying to cut down to sub 6.5kg. My only issue was the single strip of metal that was it's frame. It was pre-bent but it dug into my spine near the base. I did use it a bit without the bar. Supposedly the bar could be modified to fit but it was seriously rigid when in tried.
Don't let my experience put you off, they're solid rucksacks IMHO and I reckon if I started with one of their better/newer rucksack models before customising I'd probably have ended up with a perfect sack for me. I went cheaper than I should have.