The closest one to perfect I've ever been to was in California, about 10-13 years ago. (Before all the B.S.) B & B sales in Westminster CA, near Huntington Beach. I have no idea if it's still there or not. They had 2 stores, and one of them was where the cops went for more firepower (AR-15's) when those guys with full-auto AK's and bulletproof vests robbed the bank in L.A.
Anyway, the store was HUGE! Forklift pallets of ammo for sale and over 20 sales people working the floor. You actually had to take a number to get service, but never took more than a few minutes. The prices were outstanding. At the time it was a 2 hour drive for me, but I did it many times.
They had their handguns in normal display cases, and they had one of each model under glass. At the time they didn't carry a couple of brands like "Star" for example. But in every other brand they had one of each model. They had guns like Wildey's, Desert Eagles, Freedom Arms .454's, in the dozens or half dozens. I don't think I've ever seen more than one Wildey for sale at a time anywhere else since then. The most amazing thing? The guns under the glass were all display models!!!! My buddy bought an HK SP-89. The let him see the one under glass, and when said "I'll take it" they put that one back and got an unopened one and filled out the paperwork. Same thing with my Springfield 1911 that I bought for $339 in 1992. At the time the best price I could find for the SA was $479.
So, I guess my ideal gunshop would be similar to the above, with a complete shooting range, and you would be able to rent any gun you wanted, not just a select few. And, have holsters from some of the custom makers available instead of a little wall with 6 year old "Uncle Mikes" generic fit-all holsters.