Board Stackers offer design flexibility.
Press Release Summary:

Original Press Release:
Board Stackers from Samtec Offer Design Flexibility
Stacking of printed circuit boards at custom board spacings can be accomplished in .005" (0,13mm) increments using a variety of standard Samtec board stacking headers, board stackers and mating socket strips.
On .100" (2,54mm) pitch, Samtec offers single, double and triple row through-hole headers (MTSW Series) and stackers (ZW Series), surface mount board stackers (HW Series) and shrouded headers (ZSS Series) for board stacking. Mating sockets include standard profile, ultra low profile, pass-through and sky-scraper designs with a choice of contact styles to meet any application need.
For micro pitch, board stackers are available on .8mm (.0315") pitch (AW Series), 1mm (.0394") pitch (MW Series), .050" (1,27mm) pitch (FW Series), .050' x .100" (1,27mm x 2,54mm) pitch (DWM Series) and 2mm (.0787") pitch (TW Series). Most are available in both surface mount and through-hole designs. Standard headers and shrouded options are available. Additionally, 2mm (.0787") pitch sockets (ESQT Series) maybe specified in increments of .005" (0,13mm) board spacing. The entire 2mm (.0787") offering is available with up to 6 rows of 50 contacts per row.