He already has a good start on some of the best amps. There should be a community round up...to send David their amp, for like a month, and pay shipping both ways. This way David wouldn't have to pay and you could get like 50-60 amps reviewed with an awesome selection of cans.
DACs might be a little harder. You could do the same thing, as above, with low to mid range DACs. But those Ferrari DACs...which david owns one....would be a little more difficult to round up. There are about 5 ish that play in this league and they run from 12k-100k. But it is the low to mids we would be most interested in.