I got really bored and remapped the keys in the new DS2win to make my DS control my World of Warcraft game. THe new DS2win has a built in gamepad mode, which i dont think I used. DS2key also has this feature which i used before.
I remapped the D-pad to moving functions and ABXY to casting spells.
I was playing World of Warcraft with my DS for acouple 10 mins.
Of course it wasn't completely playable, frame rate very slow, little lag in controls....I just thought it was really really funny being able to play WOW through my DS sitting on my couch.
Ps. DS2Win already uses your touch pad and pen as a mouse replacement if you please. Can select a file, then you must have a button on the DS mapped to your mouse clicking buttons.
I remember reading somewhere that you could use the DS' touchscreen and stylus as a mouse replacement, using an N-Card (or clone thereof) with its Slot 2 flashing thingy: When the Slot 2 device is connected to your PC via USB, stylus movements on the touchscreen are translated into mouse movements on your PC.
I'm not sure, if you need an extra (DS) app for that though. I've always meant to get an N-Card to try this very function, but haven't gotten around to actually doing it (yet).
Granted, it's not exactly a gamepad replacment, but nifty nonetheless.
No clue if the N-card can do that, but I can do that with my GBA by using a Flash2Advance USB linker cable and the JoyToKey program to map joypad button presses to mouse controls. I made two profiles, one for mouse control and one for Firefox control, and actually found it relatively easy to browse the web with that combination, switching between the two.