This patch adds an option: "--indent=single-tab=X" that means the first level of indentation is a tab, with the rest being followed by spaces (uses X spaces per level of indentation).
I've updated the patch to apply cleanly against revision 431 in trunk - single_tab_vs431.patch. (The patch affects several files, and was created using TortoiseSVN).
Could this be integrated into the main branch? I'm happy to make modifications that may be necessary.
This formatting seems rather strange to me. Where else is this in use, besides your project(s)?
I don't think this would be useful to enough users to include.
The changes aren't extensive and you should be able to add them to your personal copy of artistic style.