I'd say, let it be the way they want it.
Honestly, after reading through both the deletion discussion, and several other *very* heated debates on Wikipedia, I turned my mind, from `We gotta have Wikipedia entry' to `Let them have it the way they want'. There are at least two reasons.
First, some wikipedians seem to be quite unhappy with having an article on matter they consider not notable. And, from the point of view of some of them, Colemak is but an uncommon extension to an uncommon OS, Linux. They tend to be very vocal about it, too, using colorfull wordings and whatnot. Of course, we know well it isn't the case anymore, but we can't yet easily prove, or support it. At least in a way convincing to them. If we push again and again, we'll just develop bad fame; that would do anything but help.
(( Note, I don't assume any bad faith from their side. It's the other way around, actually, they may have more experience running an encyclopedia than most of us... ))
Second, I am sure they will be more than happy to hold an article on Colemak once there is second or third independent publication giving Colemak some credit, in a reliable (their meaning) source. Of course, not being featured on Wikipedia lowers Colemak's chances of being spotted and written about, but it will happen at some point, for sure.
Anyway, there is more to publicly open wikis than just the Wikipedia; maybe we should start by seeding them? http://en.citizendium.org/ comes to mind first. After all, aren't we accustomed to using an uncommon alternative to a dominant `standard' of the keyboard layout? ;)
Also, non-english wikipedias seem to have somewhat independent rulesets and consensuses; perhaps some of them would be happy to host an article on Colemak? I'll check withe the polish one soon.