Extending the do-notation

Sometimes I need to write code which looks like this:

do x <- m1 let y = unzip x ... -- never using x anymore

I thinks the following extension to do-notation would be useful:

pat <- exp1 # exp2 ; exp3 would be rewritten as exp2 >>= ((\pat -> exp3) . exp1)

so that the above example could be rewritten more compactly:

do y <- unzip # m1

I think the biggest problem with this extension is the choice of a proper symbol. Does this extension already exist ? (I only checked the Haskell 98 report).