Joking aside, that's more or less exactly what I've been visioning for the last week. Not wanting to put out the money for a new pack, windrider or such, I'm going to make my, second, own pack.
I too have been looking at the McHale packs for inspiration, lately also at cilo gear.. but keeping the weight down -> frameless. Kind of hard to decide for all features vs weight though. I'm opting for a do it all pack, including travel...
Think the dimensions would be quite like yours, but with a roll top closure with Y-strap and some sort of daisy chain / buttonhole webbing like yours for attachments. I've also been thinking about the stretchy, not mesh, material some manufacturers use for outside pockets. I'm a bit sceptic about the mesh catching twigs and stuff when buschwacking/putting the bag down... Dreaming of attachable outside pockets.
How many pieces of fabrics have you used? (back, front, sides, bottom etc?). My style is trying to keep the number of pieces down, reducing seams and water leakage.
Thank you very much for sharing!