Oops!Compact crankset that is.

I'm not so sure about brands, but I know that lots of MTB cranks get that long. If you have a clamp-on FD, you can just get a mtb crank, bb and derailler. Not sure why youd want such a thing for a road bike though...

TA makes their carmina and vega cranks in those length ranges. they both feature bolt-on spiders for different BCDs/applications.

Welcome back. (I assume we won't be seeing Mr. mooncake around much anymore?)
Cranks beyond 175 are very rare these days. I'm running 180mm XTR 5-bolt (back from 1995 when it still looked like a classic crank) with a 102mm D/A square-taper bottom bracket to get correct chainline with a road bike. 50/36/24 chainrings. So I've got a compact with a bailout gear for if I ever go to the mountains. So yeah, old MTB cranks in 110mm bolt-pattern are the closest that you'll come. You'll probably need to get new chainrings. Look around on eBay for pre-1994 XT or Deore cranks in 110 bolt-pattern. Use Sheldon's bottom bracket database to figure out correct bottom bracket length (you'll want to go 5mm shorter for a road bike than the "correct" bottom bracket for the mountain crank, as the road rear wheel is 5mm narrower spacing - this is why I'm using the 102mm D/A bottom bracket with my XTR crank that was intended to go with a 107mm).
Here's a look at my setup:

P.S. If you go through Peter White Cycles, you can get the TA Zephyr triple in 177.5 or 180 for $365. Beautiful crank, and takes a 120mm BB, so you can go with a narrower BB and run it as a compact double if you want.

Shimano. Dura-Ace is available in 180 and probably 177.5.

I think Stronglight does a 180mm compact crank as well.

Well, Shimano's compact crank (which looks like the D/A design, but has a 110 bolt patter) is listed only up to 175mm.

The TruVativ Rouleur GXP Compact comes in 180mm. It's a new 2006 model, so I'm not sure if anyone has it in stock yet.

The Stronglight Z-Light also comes in 180mm. Uses an ISIS bottom bracket.

Would you like me to tweek the title?

hi565

You could, but no real need now that the topic has been answered pretty well. I guess it would be useful for future people searching the forums, so you may as well change it.

Alllllrighty

hi565
Mod

Another option, that can go even longer: Zinn Cycles. Lennard Zinn writes the mechanics column in VeloNews, and knows his stuff, and also builds custom bikes for really tall (and really short) people. He thinks that crankarm length should be proportional to rider's leg-length, which I'm not sure I buy (various weird physics reasons come into play here), but he makes crankarms in all the major 5-bolt patterns, up to 220mm length. So if you're interested in trying 190, as Indurain apparently used in the time trials, Zinn's your man. They come with bottom bracket, and counting that are about as expensive as the Specialties TA cranks. Here's a picture with link: