For a short-term solution, it's a rather good fit for the problem at hand, I must agree. The only issue I'd have with the idea, considered long term, is that it would puts decisions about Pike's assets under the direct influence of random Lysator members (via semi-yearly member meetings empowered to vote through anything above the heads of even the board), who might have other ideas about Pike than we do.
In practice and in the short term, it's pretty much a non-issue, though; I'd certainly trust Lysator to act the credible other part to prove a non-profit, non-Martin Bähr organization in this context. Plus the last member meeting wasn't that long ago. :)
We chose IDA over Lysator for the reasons above to avoid any potential long-term issues with shifting board leaderships and the like, but presently (and in the past) it is and has been a both very stable and trustworthy organization.