Hi there.
I think I just found a very nice D3D testapp: fr-025 by Farbrausch. A nice, small (8.2MB) graphics demo, already works somewhat with Wine (starts, plays, music and everything works, good performance), but lots and lots of effects are simply missing or wrong. It does quite a bit interesting stuff wined3d doesn't seem to handle: strange viewport handling, glow, blending, reflections, blur(?). So many unimplemented features I won't even dare to file bugreports for every single one... :)
It's the all-time most popular demo on pouet.net (obviously, given it's called "fr-025 - the.popular.demo" ;) ) You can get it at: http://www.pouet.net/prod.php?which=9450