What you have tried and how is your deployment structure?
If you download the kitchensink example it should be deployable.
Danke schoen, Wolf-Deiter for responding. Sorry for the lack of details. I did finally figure it out.
For the record....
What I had tried:
adding org.slf4j to Classpath in MANIFEST.MF
added org.slf4j to WEB-INF/lib
did 1 & 2 at the same time
added jboss-deployment-structure.xml with org.slf4j to dependencies
Finally I looked very carefully at the stack trace and the problem was that org.jboss.logging could not find it. It also could not find org.apache.log4j. Sometime yesterday evening while doing something mundane it occured to me that the org.jboss.logging was the module that had these dependencies, NOT my app. When I added them as dependencies to org/jboss/logging/main/module.xml, the thing deployed without a hitch.
Here is the module.xml file for 7.1.0.Final/modules/org/jboss/logging/main that worked
<module xmlns="urn:jboss:module:1.1" name="org.jboss.logging">
<!-- Insert resources here -->
<module name="org.slf4j" />
<module name="org.apache.log4j" />
Turns out I understand it after all!