I try to note any I come across but most rom hackers I meet that favour non windows operating systems (I met a couple that prefer various flavours of BSD) will tend to make do with WINE or a VM or code something themselves (usually with something like python and on rare occasion java).
might of interest (in some ways it is better than most GBA/DS capable tile editors).
Along the same lines you might want to poke around in devkitpro to see what you can drum up there.
I did once have a good linux hex editor (almost on a par with winhex/xways and hex workshop) but I have forgotten the name. http://wxhexeditor.sourceforge.net/
might be worth a punt in the meantime.
Becoming even more useless I did once stumble across a couple of GBA/DS known compressions that got implemented on something that could run on linux but the name escapes me even more than the hex editor. There are a couple of open source projects here as well though.
Most of the patching programs in modern use started as unix a like projects so that is OK.
I am probably supposed to say IDA has long had a linux version.
ndstool has had a linux port/rebuild or two over the years, I am not sure of anything better though.http://codinglab.blogspot.com/2007/07/nintendo-ds-homebrew-under-linux-ubuntu.htmlhttp://dev.jmoiron.net/trac/rom-seimei/
Deufuefeu did a bunch of linux stuff for his various projects on the DS although most of that was python and game specific.
I shall scour my bookmarks and such to see if I can not get something sorted- video encoding of the sort I like to do has become OK this last year and if I can get a half decent rom hacking toolkit set up I might well consider a switch as and when this install is beyond saving.
Edit: Pending something nicer dsdecmp did have a java versionhttp://dsdecmp.googlecode.com/svn/trunk/Java/
is said to work with WINE