Wario Land 4 would be fairly easy, assuming you make the sprites under SNES or GBA limitations. Heck, you could probably sprite swap Wario Land 4 with graphics from Touched or DIY with minimal extra work needed. I added the graphics from Ashley's intro and game over screen to my SMW ROM hack with no issues.
The Game Boy games might be another story. You'd have to really be limited in colour/tile usage if you wanted to include WarioWare character sprites in those. It'd be doable, but you'd need real Smash Land retro style graphics to make it work. You might also have to squint a bit to see which characters are which...
It's only for the pre boss intro scene (think like Banjo Kazooie with boss sub titles), but hey. I also ripped some other things from her intro, for other uses:
And ripped this for anyone who wanted it (since I couldn't find a use for it):
And heck, there's actually going to be a level in Ashley's Mansion with the character as a boss that Mario/Luigi/whoever fights. Still not decided whether I'll include Red in some fashion, or what exactly the mansion level would entail content wise. Nintendo haven't shown us much of the inside of the building yet...
I wonder now if we could get an Ashley sprite for Mario/Luigi, and possibly Ashley's Mansion could be the final castle. Something like Ashley has to travel to take back her mansion that was stolen from her.
