I would not recommend this, I have a friend here that has several big hispanic sites and he gets .01 or less with adsense, and there are not a lot of big affiliate companies for hispanic countries.
"spanish speaking countries" How many are there? if u think there are few than go for it. else, u can build a standerd english site, and have a spanish version seperate.
Well, there are many spanish speaking countries. Most are very intertesting, with very nice people and incredible cultures. But only Spain (and soon United States ) has wealthy websurfers and wealthy advertisers. So in most spanish written sites CPC are quite low, so you will need a lot of traffic. I'm from South America and prefer to build sites in english: gringo = dollars. Anyway, you can try. Maybe we can find a niche together.
I tried some ringtone offers with Spain traffic and got a few conversions (ppc). The challenge, as mentioned above is finding affiliate offers and good Spanish speaking markets. I'd start with these 3: USA, Spain and Mexico. Good luck
400 millon spanish speakers is worth of trying....but as someone wrote here...the CPM is lower than with english sites....