seeking good annual vegetable polyculture / companion guide

I am helping out some folks who are working together to do a vegetable garden.  Most of what they want to grow are the common annual vegetables, however other annuals or perennials will be considered if they could be used to create effective polycultures or guilds with the veggies.  I have seen some companion planting lists including wikipedia's, which have been helpful but not as good as I expected to find. Any solid resources for this would be appreciated.

already have 3 sisters covered thanks to Gaia's Garden. 
Zone 5
Thank you

I just talked to a permie who successfully planted onions in the strawberries......sounds like a great pair....intercropping (old fashioned word, i know).... and with a 3rd or 4th addition, could a 'polyculture' ?  How about broccoli among the potato plants?  Carrots among the lettuce?  What third parties?  Other poly's that work productively?