The boxset or slipcase complicates the whole process quite a bit. Plus I wanted to limit the boxset to around 500 and it's already approaching 600 because of demand. It's a good problem to have but I don't want to make it unlimited because I don't want to over-promise anything.
I used Regent Publishing Services to print Volume 1 and I am very satisfied with their service. If you have a high end book that you need printed then I highly recommend contacting them to get a quote. Here is their website. Tell them that I sent you. :)
Don't see the answer to your question? Ask the project creator directly.