We have been keeping Lilah's "walker" (which is really a standing wheelchair) at school. Unfortunately it's super heavy and awkward to get in the car and, although it breaks down into smaller pieces, that wasn't very realistic for everyday. She can't stay in it as long as her wheelchair and she really needs both at school, so we just transport her wheelchair everyday.
We brought it home for Christmas break and have been so glad to see Lilah's progress. I sure wouldn't say she's 'walking', but she likes the positioning in this better than her wheelchair and she's more motivated and faster to move in it. Most importantly she's happier for a little longer in this than her chair.
Lilah pushes herself around with the wheels, just like a wheelchair, but it positions her upright, so that she can theoretically bear weight on her legs (which she does very little). The challenge has been finding a good spot to use it. It has a very big 'footprint', so even though she is little, she bangs around the house in it, getting frustrated quickly with doorways and cabinets--even though our house is very handicap friendly.