Generalised rbind/cbind

Dear list,

Is there a generalised form of rbind/cbind for combining
matrices/arrays into higher-D structures?  ie. if I have:

a <- matrix(2,2,2)
b <- matrix(3,2,2)

how can I get

array(rep(c(3,2), each=4), c(2,2,2))

?

It seems like this would be the job of a generalised abind function:
abind(a,b, along=1) == rbind(a,b)
abind(a,b, along=2) == cbind(a,b)
abind(a,b, along=3) ==array(rep(c(3,2), each=4), c(2,2,2))

Thanks,

Hadley