[lambda]

That only addresses the one point (expense of the test boards), which as I pointed out, is the one major problem that has been solved (I consider a $90 dev board reasonably affordable for tinkering, so a $70 dev board is better, but not by much).

It doesn't seem to solve the other two problems, though I suspect that solving the second (lack of open tools) would go a long way towards solving the third as well (ubiquity of hardware available to target).