Try "Groove Me!" which is just beside Trudering u-bahn station
Truderinger Str. 265
81825 München
Berg am Laim
Phone: +4989420179
Fax: +49 89 42 01 79
http://www.groove-me.dehttp://www.munichnights.com/bars/bar_grooveme.htmI was there a couple of times and it was good fun. Very small place with live acts on an unfeasible stage. Worth a visit!
The Dub Irish bar have rock acts on quite regularly too.
If you come across any more let me know. I'm on the lookout for somewhere like wot you've described too.