I'm from KansasCIty. These are the shops that I know of that are doing work. But there is sometimes guys building at home for people too.
Lona&Sons - KCMO (Hydraulics/Air/MaybeBodywork?)
WildChild's - KCMO (Everything)
StreetRiders - Independence (Hydros/Air only I think)
Vargas - KCMO (Everything I think)
Ace - KCMO (Body only I think)
MoKanKustoms - Lee's Summit (Everything)
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Clubs that I know of with some mini styled rides are-
Modifiers
Definite Obsessions
Twisted Impressions
ScreetHos
(Might be more now? Bagged s10s have been popping up so that might cause some clubs to spring up. But it's usually all the same clicks just ask around the street racing scene for info on minitruckers.)
The Kansas City street racing site is KCSR.org (It has a minitruck area)
Goodluck man