Thank you so much everybody for the replies.

I may have just stumbled upon my answer in my last couple of days of research!

Roland will release the DR-880 drum and bass machine in two weeks. It has 500 patterns and uses all of the bass and drum samples of their SRX cards.

You can program in the chord recognition (no realtime arrangement) and store up to 100 songs.

This thing is perfect for me. I really want my acoustic accordion to be the center of my performances. I really only need drums and a nice upright bass sound. All of the other instruments really just took away from my accordion playing.

This unit is $450 street. I can sit back and have a beer as I program and store all of my chord changes for the standards I play, and then just use it as a drum machine for the obligatory polkas and older Italian tunes. 100 songs is plenty for me.

You can even use USB for playing SMFs but if I program all the changes in myself (complete with intros/fills/multiple patterns/endings)I can alleviate the need for SMFs.

Sure it's lacking a lot of functionality for the dedicated arranger folks but I think it's the answer I have been looking for. Saves me from purchasing a $3000 Midi Accordion and a $1500 antiquated arranger module. Also allows me to NOT bring a laptop with me to performances - something I personally was dreading.

Thanks again for all of the suggestions.

Tommy