It's been about six months since I've run through this, but at that time I found the following ISO590mm a.k.a. 26x1 3/8 a.k.a. EA.3 a.k.a. 650A tires available on the web, at my LBS, at hardware stores or at big box stores:
Bell Sports Streetster (folding)
Chengshin C638
Continental City Ride
Hutchinson Junior
Innova Cloud Nine
IRC Super Gold
IRC Super Seed
IRC City POPS
Kenda gumwall
Kenda Cross (knobby)
Kenda K40 Street
Michelin World Tour
Nutrak Traditional
Nu-teck (airless)
Panaracer Col de Vie
Panaracer ST Daily Commuting
Pyramid gumwall
Pyramid Sunlite Hybrid Nimbus
Raleigh Record (NOS)
Rubena Flash V66
Schwalbe Delta Cruiser (available in cream color)
Schwalbe Marathon
Schwalbe Marathon Plus
Schwalbe Speedway Pro (knobby)
Specialized TriSport
Vittoria Randonneur
Vredestein Perfect Tour
Vredestein Dynamic Tour
Vredestein Classic
hth
I meant slim as in 650b slim. There might be more selection in 650a, but both 650a and 650b have what I would call, slim selection, in comparison to 700c or 559 (26" MTB). I have some 650a tired bikes and 650b tired bikes. Tire selection, on the whole is slim. I'm perfectly happy with what is available, but I still consider those sizes, along with others (not iso 622 or 559) as having a slim selection.