I want to take some longer bicycle trips. Instead of having to put on sunscreen all the time, I'd like to get the kind of thing I use to wear in the US when hiking. It's a very light, wick-able fabric long sleeve T-shirt that offers substantial UV protection like this one from Patagonia:

http://www.patagonia.com/us/product/mens-capilene-lightweight-crew?p=45641-0-UWTB

Anybody know where to find something like this in Bangkok? Oh, I'll also need a good hat to provide shade from the sun without being too hot. Etc. Thx.

Just use a long sleeve cycling jersey, found in most bicycle shops