Been to PDC a few times (recently there for 17 nights over April/May) like you I am a rock fan and like my fix of guitar music. Have listed below your best options IMO of course.
Charlies Bar - Skin & Hide
I think the best band in PDC play a lot of good covers and many great rock songs
Also try and catch Rory Gallagher who is on before Skin & Hide he is very good.
http://charlieslanzarote.com/
O'Reillys Bar - Chancers
Good band play mostly indie songs but also a good few rock songs, do a great version of Hey Joe, also play in Mulligans on a Saturday.
Mulligans - Usual Suspects
Again a very good cover band who do a few rock songs
American Indian - Question
See Usual Suspects
These 4 are as good as you will get in PDC, hope this helps.