3D Systems still sells the heads. But when they quit and all the old stock runs out from places like fleebay I assume its the end of the line for the printer. If and when that day comes and I still have a use for the printer I might just hack the frame with another print head and throw an arduino in it to control it. It looks like there is some progress on open source software http://pwdr.github.io/ Plan B, an Open Source 3DP (powder and Inkjet) 3D Printer : 12 Steps (with Pictures) - Instructables
I have been printing more molds with Ultracal30. Seems to be doing ok although brittle and not so strong and not a very clean perimeters. After realizing that plaster chemically sets using water instead of drying I quit putting my parts in the oven. I think it was doing more harm than good.
The magic ingredient the purpose sold 3D powder has seems to be PVA as far as I can tell but I have heard conflicting information if this is polyvinyl alcohol or polyvinyl acetate.