Does a T meet this criteria?

[boina]

B. vagans, B. albo, G. pulchripes, G. actaeon

Yes! I was thinking about mentioning B. vagans and G. actaeon. G. actaeon are pretty rare, at least in Europe, and can be expensive, but B. vagans? They are pretty, more colorful than albopilosum, reasonably calm and very easy to care for. Around here you can get a confirmed female for just a few Euros.

My vote goes out to Aphonopelma chalcodes, hands down. You're in the States, meaning you can pick up an adult female for about $50. They are slow growing, so you'll want an adult. Other than that, they meet all your criteria. They max out at 4", they're the definition of docile, they're very long lived, and they're one of the very few arid species that is actually active. Keep it on bone dry substrate, throw in a paper ball for it to play with (because it will), and you're golden.

They play ball??? Now I want one. Great - my wishlist gets longer and longer.

 

[BobBarley]

They play ball??? Now I want one. Great - my wishlist gets longer and longer.

To my knowledge, many species, especially terrestrials will also.

Another vote for A. chalcodes, and maybe a G. iheringi if that increases the buoyant force the water exerts on your boat better.

 

[EulersK]

G. iheringi if that increases the buoyant force the water exerts on your boat better.

Floats your boat! Bahaha