This takes a bit of putting together, but how's about going as a sex change?
Get an old suit and shirt and cut down the side seams, so the front and back are separate, but keep the arms whole and attached to the front -it's easiest if you then sew the shirt to the jacket front to keep it all together. Stitch some elastic onto the legs of the suit to hold them round your legs.
Wear the front of the suit and shirt with a tie as normal, but get a bra, knickers, suspenders, stockings etc. that you wear so they're visible at the back - ideally stitch the bra and pants onto the suit to keep it held together.
Sounds complicated I know, but don't worry about doing any fancy sewing, tacking stitches will do.
When you first walk into the room, everyone will call you a boring *rse when they see you in the suit, but when you go to the bar, it's practically guaranteed to bring the house down. 8)