Well good news regarding the brass top/spacer for the MPC-X38! I called DangerDen and asked about it, and they said you can still order it. All you do is order the Maze4 Chipset Brass Top Conversion Kit, which is here:
http://www.dangerden.com/store/produ...&cat=45&page=1

All you need to do is make sure you select "Intel 975" for the top style, and then when you are placing the order, put in the customer notes that it is actually for the MPC-X38.

I've ordered one