Allright, so I been playing King's Bounty for a few more hours than I really should (it's kinda addicitive), and I've by now chewed my way through the Swordsmen that you can buy from the Capital. What I'm wondering is, do the troop vendors ever re-stock? As in, are new troops ever trained so you can buy more of them, or is there a finite amount of troops you can ever recruit? Does it take a certain amount of time before there's a regeneration of troops at a vendor?

Some vendors will restock - chiefly, some of the important-looking castles, such as Darion - but most won't. Typically they'll restock as you advance through the main plot quests.

After solving parts of the main quest most capitals will offer an infinite or almost infinite number of units of their race.
vendors will also restock although more rarely and almost never in infinite number.

Eeek! Ach... shame. But thanks for the answers :)

While you're waiting, you can get more from the Arlania castle.

Generally, they don't restock except on certain circumstances. Which is rather annoying, and actually what kept me from finishing the game (There's a part where there's a huge difficulty spike and you end up in the rather horrible position of only being able to fight with monsters much stronger than you, who all can nearly wipe your army on a single fight. And since restocking isn't an option for too long, well... Its a game over of sorts.)