Hi hep,

I not sure of the current prices for the Roland MDX-15, but last I seen they were about $3000.00 US.
Best to check if there's a Roland Distributor in your area or country & get the current price.
http://www.rolanddg.com/company/d-list.html
I think the Fourth Axis rotary attachment is around $1500.00 to $1600.00 US, but you'd need to check with Fourth Axis for their price.
http://www.fourth-axis.com/

regards Colin