I recently got a new van where I'm fork mounting fatbikes inside during poor weather. I wanted a wheel bag for this, and it turns out that the IKEA DIMPA storage bags will fit a 27.5 x 3.8 wheel with no issue. (This is on a Mulefut 50, and it'd zip up with no issue. Looked to be plenty of room for 26x4.8 as well.)
Since they are $6.99 each this is far, far cheaper than a lot of other options. And it's just enough to keep the studs isolated from the vehicle to avoid damage.