My neighbor who is a builder said that hardwood over hydronic is problematic and they don't normally do it.

However, I'm looking at installing the following 2 woods over floors with hydronic heat:
- Bamboo (either prefinished, or unfinished)
- Oiled 8-10" wide Brazilian Ipe planks

I have concrete in the basement, and the upstairs does not have the floor heat installed yet. When I install the upstairs floor heat, I will likely lay down the tubing and pour 1" of gypcrete over it.

Does anyone have any recommendations? Is a glue down install better for this sort of thing? Is there a better option than gypcrete when installing hardwood over the top?

There are various types of radiant heating systems. There are underfloor types which maybe better for a retrofit situation. Easier to repair as well. The ONLY kind of floor that is usually successful over radiant heat with gypcrete is a floating floor. And that is what I'd recommend. There are many nice, and wide, engineered plank floors that will work. I would NOT recommend a solid plank of any species. If you decide to go with an underfloor radiant system, this type of engineered plank floor can be glued and/or nailed. http://www.floorlayers.com/advantage.htm