I think [H]ard|OCP used to get company parts, but they seem to be buying their parts now, especially when it comes to specialty pre-builts. To me, that can work if you have money coming in as you can get a regular boxed product from a retailer and not get the selected part from a company while regular joes get the crappy, units that the company usually puts out.
Us? Reviews are pretty scarce these days, since 98% of them have been done by me. I'd love to buy new parts, but I've got other things I need to address with my money, so getting review materials is going to have to wait until I get some disposable cash.
I don't know if it's the case for every site, but we've not had a lot of success with manufacturer's replies let alone getting a product in.