Hi Joy,

I have to preface my response with the fact that I never went to my
prom, nor do I use a wheelchair, BUT...

When I was in a wedding this past summer, looking for a dress and shoes
that worked for me was not easy...Personally, I found that anything that
was at all tight-fighting or straight cut past the waist was impossible
to walk or sit in without looking and feeling ridiculous.  We ended up
getting a simple A-line dress with spaghetti straps that was tight
fighting through the bodice/waist and then flaired out to the ankle.
There was no poofy bow or crynolin so when you sat down it looked very
pretty and "flowed".  As for shoes...Sears has some awesome dyeable
white dress shoes...2 1/2 inch heel with a strap across the
ankle...$29.99.  Not bad for those of us who wear out dress shoes with
one wearing!

Hope this helps!

Linda