I love the look of a randonneur bike with the boxy bag in the front. I am considering making one for myself so I can make it any size. If I am going to go through the work, I would like to be able to fit a laptop in it easily. My current laptop measures 12.65" X 8.35". That is the smallest I would consider. The largest replacement I would consider is about 15.75"X 10.15". Would a 16" x 12" X 12" boxy bag work?

The largest non-custom front bag I have found online is the Waxwing Porteur at 14"x9.5"x10" . What do you have that is that size or bigger? Is it awkward? For the record, it will be going on a low trail bike.

Waxwing Porteur for reference-https://www.waxwingbagco.com/store/p...g_Porteur.html