Last spring I bought my oldest son a trio of boxer briefs from SublimeThreads. As many etsians do, she offers custom listings--so I bought a generic "3 boxer briefs sz 18m-8yrs" listing, then selected my fabrics from her flickr page...or rather, I let my 8yo son select the fabrics...guess what he likes?!
I can see that they are well made, with non-irritating professionally finished edges. He tells me that these are very comfortable, and based on how often they go through the wash, he seems to be inclined to grab them first if they are in his drawer.
So here are two thumbs up for SublimeThreads' custom boxer briefs!