So I haven't really been thinking about a different reward for reaching my goal ... and in the meantime, it's become clear that there is at least one type of e-book that is DRM-free for the Kindle family.
Public domain. Ah yes, those books more than 75 years old who've not had their copyright renewed. Places like literature.org and Project Gutenberg have collections of public-domain works in electronic format. Most of them can be ported easily to the Kindle or to other reasonable reading devices, and there are conversion programs for the rest.
Of course, if you thought the new Barnes & Noble e-reader was a good idea (we're a financially sound business with original ideas! no really!), think again. Yeah, for some reason, they figure they need to put DRM on the public-domain e-books for their reader. Maybe they were just afraid that Borders would go out of business before they would and they needed a gimmick to make up for lost time.
So when I hit that goal and get some version of a Kindle, I'll check out those sites, hit up Feedbooks, and get myself some stuff that I can read at my leisure.
The DRM thing, well ... even Apple learned its lesson eventually, I guess.