I buy most of my bulk grain from Paradise. If you talk to Jeff, the owner, he occasionally puts out an email and fills available pallet space with requests of customers. I'm sure you can buy bulk from Listermann's as well.
I don't mean to discourage a group buy, just sayin, there wasn't a lot of interest before.
Listermann's will order full bags for you. You need to pay in advance and they will let you know when the grain arrives. Here is some pricing I got from them in May:
Briess Pale Malt 42.00 + tax
Briess 2-Row 42.00 + tax
Munton Maris Otter 48.30 + tax
Weyermann Pils Malt 52.50 + tax
Briess Pils Malt 42.00 + tax