I've seen the G20 SF here recently for $549:
http://www.kylesgunshop.com/store.php?seller=KylesGunshop&navt1=73634
I actually bought one at a show around the 1st of the year for $525 from them (see post above)


G29 in stock for $529 (only comes with 10rd mags, but can slap a 15rd mag in there with a grip extension):
http://www.woodburyoutfitters.com/category_s/1980.htm

I've placed a couple orders (had some stock on Sunday and added more today for my G21 slide), but no complete experience (cannot vouch for vendor).  They seem to bill immediately (not just a pending hold) and claim a 2 week delay in shipping.  $35 isn't a bad deal these days :-(

http://www.natchezss.com/product.cfm?contentID=productDetail&prodID=GLMF20015

Got the complete G21 slide and 2x 26 round G21 mags (oddly easier to find quickly at a good price) to go with the 2x 13 round ones that have yet to ship.  Yet to take to the range, but it should work well. 

@BlueLineFish, if you want 10mm and .45 ACP (and not .40S&W, .357 SIG, etc...), just getting a G21 and a 10mm conversion barrel will be cheaper.  Since I plan on shooting .40S&W via a barrel swap on the G20 slide, it seemed like a better plan for me. 

I picked up a complete Glock 21 slide on Gunbroker, and I'm hoping to shoot .45acp through my Glock 20 SF (or what will be a bit of a Frankenglock at that point).  I also have a couple G21 mags coming (picked a bad time to do this), and I think that's all I need.

Anyone try this?  I'll still shoot 10mm, and maybe get a .40 S&W conversion barrel to use with the G20 slide.  I'm learning options help me keep my G20 fed with bullets without shooting huge holes in my wallet!

Just arrived.  Probably the biggest loads in the concealed carry class next weekend.  I don't plan on carrying my Glock 21 that much (eyeing Walther PPS or Glock 36).

I ordered on Thursday 1/10/2013 and it shipped today 1/16/2013.  4 50 round boxes of the Premium Line - 10mm 200gr FMJ.

Great service so far.  I imagine other types of ammo may take longer, and they sent an email out regarding enhancements to their site to adjust billing patters and better manage inventory.  I think they're in the same boat as others, but my experience with them is better than two other sites I'm still waiting on ammo from.

It's also hard to find actually in stock anywhere online.  I picked one (G20 SF gen 3) up at a show Saturday, from Kyle's Gunshop (based out of Cincy, but the show was in Columbus), which only cost $525 (new w/ 2 15 round mags, case, autoloader, etc...).