It is completely reasonable.
Bitcoin Only - It is easier to accept BTC, and they need to move money fast to pay suppliers
No Refunds - This protects Avalon against people freerolling them as a hedge against BFL. If Avalon allowed refunds, and BFL shipped both on-time and within-spec, then nearly every rational buyer would ask for a refund, due to the 65nm vs 110nm efficiency gap.
No Proof - They are just being honest here. No amount of pictures / video will satisfy the doubters (but seriously Avalon, how about a video of a unit hashing...) and they are trying hard to expedite the delivery of the first unit to Jeff.
Oh, of course. And these suppliers take Bitcoin, eh? Think about that for a minute.