Well, I've made a draft working version - see attachment (pbo only).
It would really be pushing my Oxygen ability to make a fully finished addon, but hopefully this'll do for now. They can be found under Empty -> Foxholes (or Civilian -> Foxholes, but no-one is inside them).
Edits made by me (not that all these were probably required to get it working):
- added CfgModels section to config
- removed null Components from Geo LODs (Pit1)
- TxtPathSwap'd textures to those included
- simplified EventHandlers (only GetIn and GetOut, and no *£$@ .sqf)
- renamed the patch to WEK_Foxholes
- switched side to Civilian (so that foxholes themselves ought not be targeted)
- removed Crew unit
Edit: Attachment (Foxhole (WEK Edit).zip) lost in crash of 2009 - WEK