It is possible to use armors to change pretty much any stat on a soldier. Pretty convenient to represent cumbersome suits and advanced, advantageous suits both.
Unfortunately, there isn't an option for other items to interact with stats at this point. Presumably because of the complication between putting an item on or off, which does not happen with armors.
I'm pretty sure Piratez and the FMP both have armors that modify stats and the XAE does (in the MagShield, Scout, Power and Flying Armors).