SB, Twestern just completely debunked your dev kit theory. On top of that, Gnizmo is correct. The units are not labeled for resale. There is no first right to ownership or first-sale doctrine applicable (look it up).
As for the two issues you mentioned - piracy and the gag order on Miyamoto's hobbies - neither applies to this issue for the fact that both of those circumstances you mentioned are monetary circumstances. Both cost, or could cost, millions of dollars in revenue and profit while the public viewing of a Wii development kit of test kit does not have the same financial stigma.
As far as Nintendo directly saying anything about studios publicly showing their dev kits, it's more to the fact that they don't want devs/pubs releasing detailed information regarding them. If your kit happens to make an appearance during a video interview, big deal but don't go making it the focus of the interview.
The rEVOLution is not being televised
