If you spend some time on ampgarage and some of the other builder forums, you'll see there there are a fair amount of these level builders with fairly discreet set of components. The Ceriatone and Brownnote crew, to name two-have taken some time to essentially take a set of common Bill of Materials and offer those for these, staged gain "D" type circuits and either a pre-built or DIY set up. Where Moss (Brownnote) steps away from Ctone is his interface with his customers to do any custom voicing but still within a given set of options list.
There are two chief suppliers with Schematics in the open domain on the various circuits. This all started about 7-8 years ago when the hopeful DIYr's got frustrated and were taking their kits to a handful of builders
Where Brandon (Bludo) has focused on each era of HADs various circuits (and there's about 10-15) different ODS circuits alone. His builds are so specialized (like HAD's) that to lump Bludotone and even Two-Rock in with the more generalized D Circuits is a bit of a non, like kind comparison. Brandon is now one of the singular go to guys for these circuits in the US.
Clearly the PVW amps are killer though it appears that his build times are pretty long (10 months) which is where Brandon is running.
The amount of detail just in the OT's is boggling for these amps. TrainWreck clones are in the same boat though those circuits are much more straighforward. Still, In talking with some of the Wreck builders there are myriad options on the various component pairings to get it "Right" are stunning. Dizzying actually.
Ugh- what was my point? Oh well- I guess it's that the various folks particpating in the "D" style build space are not all equal. Far from it.
Here's a chunk of the various offerings or stylings that can be built to various D stylings- The Ceriatone's, Skydstrups, and (presumably) voltamps- just don't go near this deep- Now you can start to see where these custom rigs can get pretty pricey. Don't even get me started on NOS nut cases- 
CLEAN:
70's Version1
70's Version 2
Low Plate Classic
High Plate Classic
Low Plate Skyline
High Plate Skyline
Bluesmaster Version 1
Bluesmaster Version 2
Bluesmaster Version 3
Ripper Version 1
Ripper Version 2
Overdrive:
Standard Overdrive
"Fat" Standard Overdrive (usually in 70's amps)
Hot Rubber Monkey Style Overdrive
Megaplex Style Overdrive Version 1(Usually in Ripper)
Megaplex Overdrive Version 2(also found in Ripper)
Phase Inverter:
70's style
Standard
Bluesmaster
Here's a cool one for you Dumble folks-
http://www.roblivesey.com/dumble/
