DS Download Station - Volume 1 ( haxxstation.nds ) = 16 MB
On srl :
xxxx - DS Download Station - Volume 2 (Kiosk WiFi Demo Cart) (E)(Jdump) = 16 MB
Mario Kart DS (USA kiosk demo) = 16 MB
NTR-A55E-USA - Pokemon Trozei Demo = 16 MB
xxxx - DS Download Europe - Meteos and Polarium (Kiosk WiFi Demo Cart) (E)(Trashman) = 8MB
xxxx - Pac-Pix (Kiosk Demo) (U)(Trashman) = 8 MB
[EDIT]
Thanks to
ItzMichaelPhillips prints, i found a website with DS Demos
Which are smaller than 3 MBs, I'll try the ROMs that are there