Here is DOpus running on SuSe Linux 10 using Wine!
are you kidding me! it runs on linux! 
Was it a trouble free install or did you have issues?
Basically what I did was initially installed it on my windows XP partition. Then configured it up in wine then ran in it Suse Linux when I installed it as a dual boot. I'm going to try doing a full install on my laptop with Fedora 17 using Wine. I'll post an update from that install. The only thing that doesn't work so well is "drive letters" DOpus tries to use windows drive letters, It thinks the root file system is Z:. So you just have to work around that. But everything else seems to work ok from what I have seen.
You'll run into problem with Opus assuming a case-insensitive filesystem on local drives, since Linux uses case-sensitive filesystems and Opus only supports/expects them on FTP/SFTP sites or certain archive formats (e.g. TAR).
I hadn't thought of that, but think it's prob worth it even if file rename would be v difficult. Do you think that asking for a feature request where the case sensitive rules applied to the FTP/SFTP sites could be applied to the general filesystem could be applied? This would be supercalifragilsticallydeliciosly awesome! 
Please let me know how that goes! 