The low cost ready-made
Caravans (Campervans/Wohnwagen) have their wheels inboard and lots of room inside.
They are cheap secondhand and they are expandable.
A front tent is probably included, but it is the awning that offers most.
It is tempting to use the caravan as-is as they feel homely.
Indeed, for a mobile hackerspace you can use them that way.
Also for electronic workshops. Like the here in the danish Smutti idemolab – hackerspace.
But for a mobile makerspace you better approach them as a well-insulated cheap shell and build it a new interior.
Get an old caravan with good upright standing height inside (!) and remove its kitchen, seats, table and bathroom.
But leave the stove and the overhead cupboards.
Then design a mobile lab inside it.
Like this methamorphosis of the Fabricaravane in France.
Converting a caravan into a mobile lab is a rewarding excercise of a lab making a lab. A well-known trick it to simulate its proposed interior with cardboard boxes and 'play fablab'. This really lets you think about the functions in a mobile lab.
In a caravan mobile lab you can work inside with bad weather, but its disadvantage is its vulnerability and proneness to vandalism if you don’t have a proper space to store the caravan with an expensive lasercutter inside.
Because they might find this inside: an Epilog, a Modela, a Camm, computers, pencil sharpener ...
At the Fablabfestival 2015 in Toulouse FabLab Stasbourg showed a caravan with a strong air blower in its door. That inflated a huge envelope tent that could accomodate at least a dozen makers in comfort.