Hi all,
Well, I was looking for the GoAsm header file for DirectInput, which seemingly doesn't exist, and thanks to Wayne's program XlatH2Inc (and his kind explanation), I was able to make my own, and also converted the DirectX 10 headers. I would like to share those here.
Although I am no header expert, I feel the conversion went pretty well, using other DX headers as a general guide. The original files convert to something quite verbose (lots of comments,etc.), so I removed some extraneous stuff, mostly comments that would have no bearing on assembly. To edit I used a fine blade, not a chainsaw, so there shouldn't be anything critical missing other than what XlatH2Inc removed. Also, I removed references to other file includes, so each is a standalone file. One file, dx10_all.inc (.h), references all the others (in no particular order).
I went through each file by hand at least a couple of times, formatting the structures, interfaces, and then adding <> to the IIDs where they were needed. Also, I kept MS comments for each of the interface methods, and although it adds a great deal to the size of the overall package, I thought it would be better to leave those comments in the files. All are set up as 32-bit unicode headers (all XlatH2Inc options unchecked). So I hope it's what it should be. I'm not a C++ programmer, so maybe some double-checking is necessary.
I hope you get some use out of these; I know we sure need them.
I now very much appreciate how much work went into Donkey's GoAsm headers.

In order to work better with Easy Code there is an additional set with the ".h" suffix.