I’ve done a three bean salad using canned green beans, black beans, and chick peas, and it was good. Now, we’re moving on to one calling for frozen green beans, roasted lima beans, and canned cannellini beans; and, while it needs a little tweaking yet, I think I prefer this version.
It also has the advantage of being pretty darned impressive looking on a platter.
I found the original recipe in a Better Homes and Gardens magazine laying about the book store/coffee shop we slouch around with friends of a Thursday evening and captured an image of the recipe on the iPhone before we left – mostly because the magazine folk are a bunch of weasels who require registration before accessing the recipe on-line. Note to BH&G weasels: I WOULD’VE linked to your magazine, article, and recipe – providing additional click throughs, perhaps even increasing your advertising opportunities – if you weren’t busy being such… weasels about sharing.
Irregardless, I had a capture of the recipe, 
and some ideas on how I’d need to adapt it for our tastes and preferences, so I was good to go.
INGREDIENTS:
•1 bag frozen green beans
•1 bag frozen lima beans, roasted
•1 can white (cannellini) beans, rinsed and drained
•1 cup radishes, sliced thin
•1/2 English cucumber, sliced thin and quartered
•Black pepper
•Salt
Dissolve 1 teaspoon of table salt in 1/4 cup of water, pour over the green beans, and then toss to combine in a large, shallow, pan. ‘Wave for four minutes and set aside in a colander to cool and drain – the beans will be a beeyootiful shade of green.
Layer the cooled and drained green beans with the roasted lima beans, drained cannellini beans, radishes and cucumber on 
a large platter or – if you have one – a clear glass serving bowl – and season with fresh ground pepper; it’ll look wicked impressive.
The weasels – ermmm, nice folk – at BH&G recommend tossing the salad with about half of the Fresh French Dressing, which I did, but now think it was a bit too heavy for this dish. More better, I think to try a classic French Dressing, or perhaps (and this is what I’m planning to try next time I make this salad) Sanford House Dressing. In any event, add a bit of the dressing of your choice, then toss and season with salt and pepper – it will, sadly, no longer look as impressive. Offer additional dressing as an option when serving the salad.