With regard to patches: I thought there were some non-context variants of diff. In that case, even a diff does not include original code before you patched it.
Yes there is. But I actually got new versions of the tms320c54 files from Hex Rays themselves for some bug I reported.
I then modified those to add some calypso specific code.
Also, as dieter has indicated, he knows Hexrays well and I think it should be no problem to get your modifications merged in the next IDA release and/or published somewhere on their website.
Yup most of my modifications should be in the next version, I've sent them to Hex Rays.
Cheers,
Sylvain