Monster Hunter 4 Ultimate had some fun downloadable crossover events and unlockable outfits; it was possible to earn items for your hunter and Palico that paid tribute to franchises such as Street Fighter, Sonic the Hedgehog and more. Nintendo's franchises also featured, with notable examples being The Legend of Zelda and Metroid.
The latter two are arriving in Monster Hunter X (Cross) shortly in Japan, too, as part of a month-long 7-Eleven distribution. They're variations and in some cases repeats of the content enjoyed in the game's predecessor, but a cool new set of goodies - initially announced in late 2015 - will be related to Star Fox; the timing is good with the upcoming arrival of Star Fox Zero on the Wii U. Of particular note is the Fox Palico outfit, which you can see below.
The latest Monster Hunter entry has proven to be another hugely successful release so far in Japan, though there's been no word yet as to whether it will come to the West. We'd love a localised version, naturally, with the new entry incorporating some fresh mechanics and a more action-oriented approach.
Until localisation is announced we can only look on jealously at the Fox Palico outfit.