You should also know that you can ask them about customisations that aren't listed on their website too!
When I got my first Penelope Messenger, I had a notion about adding a zipper closure to the main compartment so that it has 3 zipper closures (the front and back slim compartments which are zippered by default, as well as the main compartment in the middle), instead of the default magnetic closure in the middle. It worked out wonderfully, and that is now my preferred customisation for the Penelope Messenger!
You should definitely try searching through the Massaccesi general thread here, or there are a couple of useful reference threads too, to get a sense of what other customisations you could ask about on any bag they have, other than what they list on their website. If something really isn't doable, I believe Marco would usually let you know (it can be a pretty discussive process, but enlightening too!). For the Penelope Messenger, I also like customising the shoulder strap to be removable, in addition to changing the length to something that works better on me.
I also second the earlier suggestion for MZ Wallace -- the Paige in particular works fantastically as a crossbody, and it's slightly larger than the Penelope Messenger in dimensions and capacity. I used one of mine recently for travel and could fit a
tonne in there for its size, including a foldable umbrella and a standard sized water bottle (500ml / 17 fl oz)! (My friend was amazed when I pulled the water bottle out of there
) The hardware colour will vary depending on the colour of the bag, but they do match their seasonal colours with silver hardware, so you just have to keep a lookout.
Edited to add, MZ Wallace's website also recently started offering free international shipping if your order exceeds a certain amount (specific threshold depends on your local currency, but it seems to convert to around US$180-185). Their international shipping includes any import duties payable in your country too, if I recall correctly.