Rothco vest ? not heard of those, I'll have to look it up.
Where do you buy them ?
I got mine from the Army Surplus store in Hinesville. Those vests or similar ones from other makers should be available at manystores that sell military and police gear. If all else fails you can order them online or have your local FFL dealer order them for you.
These are nothing more than safari or outdoorsmantype vests with lots of pockets. I pack a 4" XD9 in an outside-the-waistband hip holster concealed under the vest with no problem. The only comments I've ever received about my vests are "Going fishing?"