starting a waist high bed for vegetables

Hi everyone, just back from babysitting and my son tells me that the waist high planter that has been put in by the local council ( from another housing estate) is going to be his responsibility.  It is may be 30ft by 5ft and is sitting in an enclosed grass area outside their block of flats. At the moment they seem to have put some rubble in the bottom half and will (hopefully) fill the rest with some mixture of topsoil and compost.  It is a sunny open position.  I know he has had something to do with the local community "garden" close by and that they had a glut of tomatoes last year. What would people suggest as starter vegetables?  He is keen on summer squash.  I suspect that goodies may be pilfered when it is up and running, but only by his neighbours as it is not open to the street.  I don't think that will matter too much as there is plenty of space to expand into if it is seen as a success.

Onion, garlic and shallot sets. you could put muck in all but a portion of it

These beds are really productive.  It's easy to put a frame or cloche on a bit of it for some early spuds.

Tomatoes might be a bit tricky in a waist-high bed. I dunno, but I'd at least stick to determinate varieties.  Also it might be a good idea to put support stakes in for them before you start planting stuff. 

Thanks everyone for the suggestions so far.  I've just forwarded the thread to my son, please keep the interesting suggestions coming, they'll not be able to start planting out or anything until topsoil has been added but will at least be able to start planning!