TT,
Do some research on Boquete, Panama. Great climate, still relatively cheap, but going up. Only issue is not the easiest place to get to. Still though there are a lot of advantages to being in Panama over Costa Rica from an investment perspective. Just get a lawyer and pay a few hundred bucks and you can set up some beautiful stuff, if you catch my drift.
If you want something easier, they are building a number of places about 2 hours from Panama City up in the mountains. Its not quite as nice as CR both in infrastructure and weather, but at 3,000 feet the weather is a welcome relief nonetheless.
Nicaragua is just so far from being ready for serious investment. I spent 2 days there, supposedly in the nicest area (Antigua) and it was almost heartbreaking. If that is the best Nicaragua has, you can see why so many go to CR. Nothing wrong with the people and it doesn't feel unsafe, just the level of poverty and the ramshackle construction of everything probably would make you feel quite unsettled. Not to mention the weather there is horrible too, just less humidity. Maybe if you really want to get away from it all and find some fishing village along the Pacific it might work, but remember if you want it as an investment you have to think about what would drive the prices up. With no infrastructure and sure to be grinding poverty for a long time to come, its not something I would get crazy about.