I believe you are asking which wheelchairs fit in a Toyota Sienna van converted using Toyota's Mobility Assistance plan?
If so, I think it is the skies the limit. Toyota's mobility assistance plan reimburses you for aftermarket work you do on the van or any of their other approved models past manufacturer year 2001, so you can modify it however you want and send them receipts to get money back up to $1000. Someone else posted about the program here:
http://www.wheelchairforme.com/forum...c.php?f=8&t=15
From what they were saying it might make sense to call or email
www.braunability.com and just ask them if they can modify the Toyota Sienna to fit your wheelchair and how much it would cost. And then see if it costs less than Toyota's reimbursement. I would suggest only using high quality mobility conversion experts - your car is not where you want to skimp.