I'm living at Del Perro atm, but I'll check out those new apartments as well. I really wish I could find a map of the single 10 car garages (no apartment). Seems impossible to find. I want my first garage to be racers and cruisers and a single 10 car garage for jobs. I can have my Sandking, MW Mesa and stuff like that in there.
Not sure if you've found the 10-car garages without apartments yet but they're pretty easy to find on the Dynasty8 website in game. From memory there are three, all around $150k to buy, and all close together in East LS, a block or two north of the LS Customs there.
ETA: there are 6 in fact, having googled it, from $105k to $150k in price. The most expensive three are the ones I mentioned but there are also two at the airport and one at St Cyprus Flats (which I think is between the East LS customs and the docks).