talkmagic.co.uk

I have recently been putting together a mentalism parlour act (having usually stuck to close up), as the possibility of trying a few things has recently arisen.
One of the routines I have planned goes like so:

There are five envelopes, all with different symbols on the front, displayed at the front. THere are also five boxes/bags with a suprise gift in each. Lastly there are four chairs also at the front.

Four volunteers are asked to to come to the front and sit on any chair they wish. They are then to choose an envelope (whatever symbol attracts them the most). After a brief character reading concerning their choice of symbol, the envelope is opened, and a folded piece of paper is dropped out onto the specs hand. It is opened to show a number. They open the corresponding box/bag and find a small gift (it could be a really bad gift, but I'm going for a nicer version). This is repeated with each spectator. The final remaining envelope is opened to show the remaining number, the box is opened, and a really expensive item (or lots of money) is found inside.
Most people assume this is the end, however, the performer reminds the spectators that they had a free choice of seat at the start. They may not have realised the significance of the choice ot the start, but when requested to stand and turn their chair round to face the audience, a picture (or the name) of their chosen gift is seen stuck to the back of their chair.

I quite like this routine, and will be trying it out soon, but I'm sure it must have been done before. I realise the bank night effect is an old one, but I've not read about it being done like this before. THough I'm sure it must have. Does anyone know where this has been done before, as I would be intrigued to see it done.