I'll play Devil's advocate here, if you don't mind :)

What proof do you have that the nonscarce backer rewards (exclusive transformation, in this case) won't make their way as a DLC?

Why do you consider backer-exclusive digital content to be a bad thing? After all, the people who put up the money for a product that doesn't exist anywhere except as a few pieces of concept art should have some reward for believing in the idea. I can understand in the cases where BE-content makes a game completely different but if it doesn't affect the game and appears to be mostly cosmetic, where is the problem?

Keep in mind, I am taking the opposite stance for debating purposes only and I don't intend to troll you, Starmaker :D

Interesting points.

Forgive me if I am being thick here, but the bit about numbering prints could be a bit off due to the fact that at the base level, no extras just the game itself, the content is the same there's no numbering of the base content. For X amount of money everyone gets the same game. In my mind if a backer pays more than the base price, shouldn't they expect a bit more? What incentives, rewards, additional goodies would you give to those that believe so much in your idea that they want to pay far more than is theoretically necessary?

Your words:

"Specifically high-tier digital specials (as opposed to extras for all backers, like Larian's epic trunks) are honestly an insult to every low-tier backer. Like horse armor, but in every way worse. "

What about the opposite? What about being a backer who plunked down $50 or 50 Euros for the game, got their name in the credits, and some other digital, no physical goodies, rewards and then you see the game appear in a bunch of bundles and people get it for a dollar or $5? I've seen people get a bit upset when they bought a game full price a day before it went on sale for half the price or even 75%.

"Maybe pretending that physical limitations such as limited availability apply to digital goods"

I am looking at two Kickstarters right now. One is the Mighty No.9 one and the other is Larian's Divinity Original Sin. I am looking at the reward tiers for both and the only physical limitations I see are those that apply to physical content ($95 on Original Sin had a box copy, printed manual, OST CD, and a map while Mighty No. 9 has a $500 tier that involves helping to create a challenge for the game and I think this one may have been limited because "too many cooks spoil the soup" so to speak). The tiers that featured only digital content had no limits so anyone with the right amount of money could buy that reward if they so chose. Unless the "physical limitation" you are referring to means "limited because the Kickstarter is closed", I fail to see the "physical limitations" or "limited availability". Care to enlighten me on that? :D

"Incidentally, I think Larian's Imperial Edition is a great move. They were giving extra stuff for free to people who believed in the game and the company to take a dive old-school-style, before the reviews and letsplays started appearing"

Could you show me the source of this? The only place I can find anything remotely Dragon Commander-related on Kickstarter is the Original Sin kickstarter and I was sure there was a separate KS for DC as well. Yes, I used Google but not well enough I suppose :P If you're referring to Original Sin, the extra stuff applied to tiers $40 and above, unless I am reading things wrong, so if you only paid in, let's say, $20 then you didn't get the extra stuff.

Like I said before, I am just playing Devil's advocate here for debate purposes only :)

So what would you put in place of backer-exclusive content in order to entice complete strangers to give more than the usual amount to your kickstarter?