[I was doing some digging for another project, but I'm not one to waste research, so I'll put it up here, too.]
Wheelchair Dancer recently mentioned that she's wanting some
sexy, funky clothes that work with a wheelchair--and nicely outlined the ways that can be a shopping challenge (with lots of interesting links). But looking for workable children's clothes is hard, too--because so many websites for "adaptive clothing" are geared to seniors, with styles and sizes to match. (Because my son's size and age don't match on anyone's standard charts, I'm also fighting the opposite demographic--he often fits into clothes made for 3-year-olds, but he wouldn't want to attend middle school in teddybears and "lil slugger" motifs.)
So here's what I did find.
Special Clothes for Special Children (based in Harwich MA) has a doubly "special" name, but otherwise it looks like a good online catalog--plenty of practical adaptations around fit, closures, durability, washability, sensory needs, g-tubes and trachs, chair-friendly tailoring, and allergies; mostly age-appropriate, basic styles (the same company also sells adult clothes, under a different label).
Adrian's Closet (San Marcos CA) has adult and children's sizes too--their styles run mostly in the sporty-fleecy vein, with a lot of attention to alternative closure placements and easy fasteners. In the UK,
Rackety's has message T-shirts (as in "There's no need to stare, I know I'm cool" and "wicked on wheels"), tracksuits, pajamas, shirts, and swimsuits that are good-looking and thoughtfully designed (the tracksuit above is theirs). They also sell soft dolls and bears who use wheelchairs.
Then there are some specialties within this specialty market.
Go Squeak and
Pipsqueakers sell toddler shoes that squeak with each heel fall--apparently to encourage walking with audible feedback, and discourage tiptoe walking. They might also work as a "where's baby?" signal in the exploring years. (Yes, you can remove the squeakers when the novelty wears off.)
Cameron's Special T's covers some therapy territory, making weighted T-shirts and similar clothes with sensory feedback function.
Babylinq specializes in beautiful, tiny clothing to fit preemies (4-6 lbs) and even micro-preemies (1-3 lbs). I remember that it was discouraging when all my tiny new son's clothes were much too big (even the ones marked "newborn"), and how right it felt to dress him in something made for his size and shape.
These clothes don't come cheap, but if the adaptations are helpful, they may be worth the difference. Kids need to be comfortable, and clothes shouldn't be more of a struggle than necessary. Also worth considering with the price: the sites often mention good quality construction and fabric, and have the kind of customer service you'd expect from small family-run stores (as many of them are).