G'day
I think the original poster is looking for a bridge rectifier, but for 3-phase instead of single phase, so he can use 1 'brick rectifier' instead of 3. I've been looking for these too, and they exist. They have 5 (instead of the usual 4 for single-phase) connections, 3 ~ ACs in, 2= DC out (+ and -). I want them because it'll make the wiring easier, neater and mechanically simpler & more stable/durable. However, the only thing is the price: Farnell (www.farnell.com) wants about 20E (25$) for one of them (15amps, if I'm not mistaken). That's a bit too much, especially when you have plenty of diodes & bridge rectifiers in your junk boxes. If anyone knows another place where they're available for more reasonable prices, I'm interested.
It surprises me that no one else uses these 3-phase bridge rectifiers; especially for the less-electronically inclined ('electrically challenged'?), it would make wiring it up much easier: 3 wires (star or delta, doesn't matter which you choose, you'll have three wires out) to rectifier, 2 wires (plus and min) go to battery/ charge regulator. The downside is that they're harder to find than single-phase versions, but they do exist!
BTW, it's quite easy to build a switchover from star to delta; after an evening of thinking, I've come up with the solution (probably a re-invention of the wheel), needing just one one switch (with 3 decks). Building it is easy, once you get the wiring diagram....
Hope this has been of help,
Peter.