Hi,
To summarize 3dmark2001 possibly uses incorrect d3d8 code but the code works fine on Windows. I tried to test the behaviour using a test (perhaps not a good test) and windows appeared to work correctly and the same for wine. Further oliver had the same problem in maxpayne2 (it uses the same 3d engine I think) and he used a similar hack.
One thing that I've learned since I started working on Wine is not to trust the MSDN. During my ddraw/d3d work I've seen a lot of such things, and the ddraw code contains a lot of comments which state that the msdn is incorrect. And at the university I've met some windows application developers which thought that the msdn is horrible.
In this case, what speaks against simply allowing rendering from sysmem textures? In wine this doesn't make much difference(as we 'only' forward to GL).
For Windows I'd say that this might depend on the driver. Perhaps in MS design sysmem textures can't be used for rendering, but most drivers eighter ignore the sysmem property completely(and place everything into vidmem), or they are just able to render from sysmem textures. If you are unlucky, you might have a driver which can't do so, and some apps are broken.