An awesome website I found about DS mods
 

http://ds.qj.net/category/Mods/cid/377

I came across this site while searching for DS Lite carrying cases. Some of the stuff people have done is pretty cool. I like the koopa shell ds.

I was going to copy/paste this link when I saw the title but I see they might have touched on it a little on that site. Not so much the same thing, I don't believe, but others have tried I guess. Anyways, a DS overclocking + tutorial. It's not in English but use a translator if you are interested in trying.

http://nds.jpn.org/nds2n.htm

Finish!Extremery daricate handy work! Good luck!

I seriously ROFL'd irl at that

That site, along with crap loads of news and rumours, has sections for mods for individual games.