I would like to support goatpig's efforts as well because Armory is mission critical software for my use case.
Although this would likely be unpopular, personally, I wouldn't mind a small non-optional fee built into the pre-compiled clients that can't be removed, so he can skim a small transaction fee and % of a point off of every transaction.
This will never happen, if for no other reasons then for reasons of privacy.
If goatpig doesn't want the money, he can use it to hire another coder.
Not for the money he can raise with donations. Once the first 25 people have donated 25$, the flow becomes a trickle. And a decent programmer probably costs around $100 per day.
The only reason I can think of that someone might want to reject funds is to avoid any tax related shenanigans. Maybe he doesn't have time to setup a non-profit etc.
Again, perhaps the income is not worth the hassle. Sadly. Armory is a great part of the Bitcoin infrastructure, but very very few open source projects are able to generate enough income to actually pay a developer.
On the other hand,
what better way to show moral support than to put our money where our mouths are - I, too, have donated to Armory in the past, and want to do so again.