Move cover page colour and blank coloured end page to doc-specific files. That way output where the colour isn't appropriate, such as Nook or the newly introduced A4Lulu output (which is the A4 book but with white cover page and no end coloured page, and so suitable for using as the content on Lulu, where the cover is separate) can omit the colour.

X:1
T:Grandfather's Tune
S:Nick Barber
N:Change: Sloe.abc
R:Reel
M:4/4
Q:160
K:D
P:A
"D" F2A2 "A" B2c2| "D" dcde f2 a2| "A" g2f2e2d2| "A" c2B2A2G2|\
"D" F2A2 "A" B2c2| "D" dcde f2 a2|
"A" g2f2e2 Bc|"D" d2f2 d4 :| |:\
P:B
"A" e4 e4  | "A" g2f2 e4 |
"A" g2f2e2d2 | "A" c2B2A2G2|\
"D" F2A2 "A" B2c2| "D" dcde f2 a2| "A" g2f2e2 Bc| "D" d2f2 d4:|