Suggestion: Vehicle vendors classified as "Industrial", taking vans from the more traditional car dealers and adding onto them with trucks. For the bold robbers who want to easily access a vehicle classified as a truck for storing 30 items during house robberies, the oddball industrial enthusiast or the dedicated trucker, all of those vehicles would be included here.
Because of their larger size, the same places where you buy these vehicles are also where you store them, having a unique pair of garages that only Industrial vehicles can be stored in although only large trucks would fall under this rule.
Any vehicles classified as a van like the Burrito would be sold here too but remain storable in typical garages.
New "Industrial" vehicles offered by the vendor would include: Benson, Boxville, BoxBurg, Yankee, Mule, Flatbed, DFT-30, Cement Truck, Trashmaster, Hotdog, Dozer, Packer, Bus, Coach
Also including trucks for trucking missions, like the Roadtrain, Tanker, Linerunner
Additionally, whatever vehicles I might have missed from this list that would be suitable.
Locations would be: LVA Freight Depot in LV, Easter Basin in SF, Ocean Docks in LS.