Hi Lee

Have a look at the CME VX range of controllers http://www.cme-pro.com/products-list/product-vx.html as you may find these give a general arranger layout style.

Also see if you can find a used Bohm Keybits arranger (The name changed to Silverbird when they changed from black to a silver finish) as these were available with and without an internal sound generator, as well as an advanced Midi setup, and so literally was an Arranger Keyboard Controller.

LS still only adapts Megavoice styles to a closer standard voice rather then play them as is, but apart from that 10.5 gives you pretty much everything you get in an arranger, and then some. (Don’t forget the GS mode so that you can also play Roland Styles)

Regards

Bill