Thanks for all of the comments. These are all good.
A bottom view of the 10mm x 10 mm active module is shown in the attachment. The connection pads are the staggered arrays on the left and right sides of the package. The module resembles a big surface mount chip and there's more room inside for other components. We've also built sensor arrays in the same modular format.
In some ways these modules are like big ASIC's that can be mounted in several ways. The second attached photo shows top and bottom views of a complete wireless sensor built around an Arduino module and an accelerometer module. We used a 2.4GHz wireless module from Anaren here. If anyone is interested in the Anaren/Arduino interface firmware we've posted it at www.potomacmeso.com and also on Github.
