I'm trying to get some work done here and then you post this. Argh. Have you no shame? Guess not.
E Middlesex
S Last of the Mohicans
N Mid morning
Y Happy Ending
A End of an Era
T Eastend (or Westend)
E Beginning of the End
C First Contact
P Leader of the Pack
S Head of State
C Compass Heading
H Midlothian
Down clues:
M Top of the Morning
L Bottom of the Barrel
P Bottom of the Heap
M Bikini Bottom
S Topsail
D Top dog
W Top of the World
A Bottom of the Sea
Back to across clues:
Y The first of the year
E The end of time
P Penultimate Paragraph (I really like this one!)
B Bikini Top
S Last Tango in Paris
S Tale of Two Cities
Then there are some other, similar clues though not of one letter:
SUM Endless Summer
SH Southside
Down clue
PI Bottomless pit
ARS Topless bars