Honestly, I do not consider Katamari Damacy to be an ideal fit for the DS. The concept of rolling a ball around a field has been done by Pac n Roll, which met with fair reviews true enough. But when you consider a seemily similar title of Pokemon Dash -- well, moving an object forward by scraping the stylus across the screen endlessly doesn't sound like the grandest of good times.
Now, Katamari Damacy could be done on the DS in a more traditional format, utilizing the directional keys and the face buttons to manipulate the Katamari, but (and do not forget I do love my DS) the DS is incapable of rendering the graphical quality of the PSP or Playstation home systems, certainly. The environments of Katamari Damacy titles are so rich in detail and miniscule objects, that I fear such a DS port would be a vague, polygonic mess.
Well I would enjoy playing Katamari on my DS and would likely buy/trade for such a title, I think it is better suited for other platforms. I can see the possibility of a DS version (after all, the DS is far more successful than it's handheld competitor), but I think it would have to undergo a total graphical makeover -- think 2D objects with 3D rendering, perhaps -- to fit the DS's abilities.