analysis: unhappiness

[s.t. bischoff]

Hi all,

I had an interesting exchange with a few generative
syntacticians/morphologists (former classmates of mine) regarding an
analysis of "unhappiness". Two things that they said surprised me a bit,
they are the  following:

(1) un- (negation, 'not') only attaches to adjectives (now this clearly
isn't the case, a simple cursory view of the etymology in the OED provides a
number of examples of un- with nouns and verbs...though to significantly
lesser degrees...in addition works on English morphology contain examples as
well)

(2) the analysis of unhappiness can only be [[un-happy]-ness]...an analysis
such as [un-[happy-ness]] is impossible (due to (1) above according to my
former colleagues).

My questions are the following:

(1) Is there a good/well grounded reason to  believe un- "only" attaches to
adjectives?

(2) What would be the consensus on an analysis of "unhappiness" that most
linguists would agree on?

Thanks,
Shannon