Ok.  I feel bad that this solve is so late, because deagol made a great puzzle that included a reference to a thread that has since died.
I have to admit that he had to hold my hand during parts of it, as i was being a woman and complicating everything  
 
  
Anyway, here it is, and thanks again, deagol, for your wonderful puzzles.
Sorry it's so late  

Would it help if I said you were hawt? 
 
 
Hodgepodge 
Home-thy? pr-gate d-mine --what's this mish-mash? 
A cure? multiply brain stuff... I am the dash! 
Danger! also a wacko, killer or freak, 
there's two acronym versions as well, I'm in all that. 
Now, dear, please don't think I'm a prick, 
but I'm proud, yes: though broken, I'm even in Oprah! 
This is the easiest place to start.  
Home
OPAthy = a cure
pr
OPAgate = multiply
d
OPAmine = brain stuff 
From these answers, we see that "I am the dash" = 
OPA, which is what we need to look for to solve the rest.
Danger = je
OPArdy
wacko, killer or freak = psych
OPAth
and OPA is in 
Opr
ah.
So going back to deagol's poetry...
A rainbow of color and light, I am 
light sheets, when in front of a line. 
in front of a 
line = 
opaline
Between tea and sea, I am loved by les femmes 
hard and dense with a glimmer --amber: a gem. 
amber:  a gem = t
opaz
Oh, but when having a whole city behind 
I will veil any glitter, twinkle, or shine. 
having a whole city behind = 
opacity
Find me there, in the middle of a reference work, 
amongst all human knowledge in several tomes. 
all human knowledge in several tomes = encycl
opaedia
Between men and use, you'll see me decay 
shriveled and dry, "no more fun," some would say. 
between men and use = men
opause
Ellie, me, are thee? Yes, try saying that, 
and beware of the big, black-spotted cat. 
black spotted cat = le
opard
Then we have his second post, where he decided to complicate things...
CPQMENHEGFMMEDDOCPQNEDHFCFMMEDDECFMCAN== 
No, no, wait a sec. Before decoding you need to de-V it. The key for that is: 3|4, 2|2, 5|1, 5|1, 4|13, 1|6, 6|7, 5|4 
De-V = Vigniere Cipher
To get the key, the number pairings represent word number|letter number in the word.
Therefore:
3.  opacity:  letter 4 = C
2.  topaz:   letter 2 = O
5.  menopause: letter 1 = M
5.  menopause: letter 1 = M
4.  encyclopaedia:  letter 13 = A
1.  opaline:  letter 6 = N
6.  leopard:  letter 7 = D
5.  menopause:  letter 4 = O
The key for the vigniere cipher is COMMANDO.
Using it we get this string:
ABEAEAEQERAAEQAAABEBEQERARAAEQAQARAQAA==
abeaeaeqeraaeqaaabebeqeraraaeqaqaraqaa== 
Which is base 64.
Decoding it gives us:
00 11 00 10 01 10 11 10 00 11 00 00 00 11 01 11 01 11 01 10 00 11 00 10 01 10 10 00 in hex,
which looks a lot like binary, so decode it as binary and get: 
2n07v2h, which looks like a tiny pic.
Which brings us to 
http://www.tinypic.com/2n07v2h.
And no, I'm not disappointed 
