I've been looking high and low for years to no avail.
Does anyone build and sell gatling guns in modern, serious calibers ?

I'm not talking .22LRs or crank operated Ruger 10/22's or AK's.

I mean a real, multi barrel gatling.

I've heard there's a guy in CA called "Thunder Valley Gatling Guns", but have never been able to locate him.
Thanks in advance.

CKMorley

Unless you are LEO/Mil, nope.

Last time one came up for sale it was around $200k.

EDIT:  Unless you meant the hand crank ones.  Those you can get, but they are pretty much custom made

ETA: I have no idea what guns Larry Gatlin and his Brothers own.

Thunder Valley made/makes full-size Gatlings in .45/70.  The last one I saw (about 1998) went for somewhere between $14,000 - $20,000.  (The range is because the gunshop owner offered it to me for $14K, but the price tag was $20K.  I couldn't quite swing it at the time.)  I don't know if the company has started back up again now that the ban is over -- they weren't affected by the "assault weapon" part, but a ten-round magazine capacity on a twelve-barrel Gatling isn't much fun.

RG-G makes ready-to-crank Gatlings in .22LR for $5700-$10,900, or kits for about $680, or plans for about $60.

There are other companies making black-powder Gatlings (using the same technique as the first Gatlings did, basically a stack of steel cylinder chambers with a percussion-cap nipple on the back;  these get loaded with powder, patch, bullet, and percussion-cap, put in a rack, and cranked through the mechanism).

Of these, the RG-G kits arguably give the most bang per buck.  But if you can afford to buy a Thunder Valley, you probably can afford the ammunition bills.

EATA: holy #&*$, RG-G's prices ain't what I remembered.  The kit for $680 will be cheaper than buying the parts separately, because it's such a pain to find all the parts, and cost in bulk (for them) is lower than buying one-offs and having them shipped to yourself.

Here's RG-G's site:
http://www.gatlingguns.net/
http://www.gatlingguns.net/pricelist.htm

Oh yeah, there are other companies which have made Gatlings, including Furr Arms, which made quite a few half or third scale Gatlings in .22 Short and .22LR.  FJ Vollmer used to buy/sell these, IIRC.