Thanks again for the tips. I found exactly what I need here:

TheDrumSource VSTi. It has a user interface just like a HW drum machine. Very basic but does just want I want. Easy to build loops and make simple on the fly changes. No swing or any exotic beats though.
http://www.witech.se/thedrumsource/

Studio Drums Free Sample Pack from here for the drum sounds:
http://www.vstplanet.com/Instruments/VST_Drums7.htm
I'll try some of my BIAB samples also.

I use this host to play the Plug in
http://www.hermannseib.com/english/savihost.htm


Tom