I have a epiphone les paul 100 and the pickups on it arent great, I love the sound on a les paul juniors dog ear p90s and I am wondering would a dog ear fit in the humbucker route or are there any humbucker sized p90s that are available?
Since it is a cheap guitar, don't throw a lot of money into pickups. GFS Mean 90 or GFS Dream 90 are good HB sized P-90 pickups and they are only $35 each.

2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate