1/8 Truggy .. or Mobster truck.. open gear too.. sometimes 2 or 3 speed too .. again, no matter with cover or not, will get sand...stones.. all the time.. Mod 1 spur isnt that bad.
Can also consider Kyosho DRX/DBX series wor .. has "semi" cover, work pretty good, it is basically a SCT, with 1/8 buggy look and size, (same 322mm wheelbase) and so call 1/9 at great price .. (1/3 of a TKI kit!)