Perhaps even more obscure because the .38 revolver can be tracked down is a M.A.B. .32 compact semiauto bought new in 1965 for $50. It was made in Spain, and it's obscure because I haven't been able to find any references on it. It was a nice gun, and I wouldn't mind getting another one as a curio
Blackhawk, the MAB is a French handgun, not a Spanish one. The model "D" is one I used to own, and even carried once or twice since it was so small and flat. Here are a few links:
http://www.angelfire.com/nh/milarm/mabd.html
http://www.marstar.ca/mabds.htm
http://www.gunsamerica.com/guns/976213074.htm
It is a copy of the old Browning 1922 pocket pistol with a shorter recoil spring retainer at the muzzle. Fairly common import about 15 years ago when I bought mine. The only bad thing was that the target grips they saddled it with were horrendous. And the chamber was a little tight, fed silvertips great but federal fmj was too fat to chamber. IIRC, they were about $75, so inflation wasn't too bad.
As for other uncommon guns I've carried at one time or 'nother:
Sterling .22 pocket pistol, sold it to my dad after it failed to penetrate 3 layers of blanket. It went off while chambering a round. Polished the burr off the breechface to stop that problem.
Colt Police Positive in .38 S&W. Bought it in mint condition for $100, sold it 2 weeks later for $450. Still miss it.
Walther PPK in .22, German ww2 issue. Sold for too little when I really needed the money.
Calco 9mm "handgun". I was in the number 3 murder rate city at that time, 100 rds of 9mm under a coat was comforting. as was the spare 50 drum in the offside carrier.
Steyr GB 9mm. Made a custom shoulder holster for it of the Allesi Bros. pattern, still carry it today when I can wear a jacket. 19 rds in the gun plus four spare 18 rd mags is kinda heavy, but comforting.
"Custom single shot .22 pistol" (Zip gun made when I was but a lad) Technically a smoothbore, but the thing really only had a chamber, the tip of the lead stuck out the end. Tossed it when I discovered such a thing was frowned upon.