I don't know why I haven't thought of this sooner but I might've improved upon the general design of the french box easel, if no one else had thought of it yet. For those who don't know about them, a french box easel is a compact version of a painter's easel with a built-in supply box where you can easily setup/de-assemble it into a carrying case for travelling around with all or most of your equipment/materials.
This version of the easel was invented during the late 19th century for mostly French artists that started to do En Plein Air (Open Air) painting. It was around when artists like Claude Monet were starting to break away from the art academies' standards of painting, mimicking the classical works of regal and divine subjects from the past at indoor museums and galleries and choosing to paint in a looser, freer style of more everyday subjects, mostly outdoors. This easel model became essential and still is when artists do their paintings outdoors or travelling abroad, along with carrying their materials and equipment. Depending on some manufacturers' models, these french easels can be priced between $100 to $300 CAN approximately.
Anyways, back to my main topic point...
Before when I bought my own box easel, it came with a leather handle and a thick cloth strap to help carry it around. Problem was that it wasn't comfortable to carry around after you load it up with your art stuff and surface board. After the first hour or three, its' weight, hard sides & edges starts to strain your hands or shoulders when it constantly bumps your sides and you got nothing other than your own feet to get around with it. I once thought to modify it to have backpack shoulder straps to help carrying it like a backpack; it would've still felt hard against my back and for hours of walking, eek!
It finally dawned onto me this year that I could instead modify it like a carry-on luggage case. You know, those airport terminals where you see most of people's baggage being these heavily-packed vertical cases with wheels on the bottom and an expendable top handle and to move around with them, pulling them along like toy wagons instead of lifting them? My box easel was already shaped similar, so why not just add some wheels to it and pull it along too?
I bought some wooden dowels and a pack of pivot wheels from a dollar/discount store. With some spare screws, wood glue, my dad's saw and a screwdriver, I've attached the wheels and supporting dowels to the easel's bottom. It doesn't interfere with the easel's other components. I can now wheel around with my box easel on the floor and can still stand it up originally too. I haven't field-tested it yet but I'm confident that it could work.
For anyone whose having problems travelling with their box easels could try out this method. Maybe it could become a new marketable feature for travelling easels some day.