Well, for concealed carry, I'd personally keep the 10 round mags in it while walking (or jogging?) around, while I'd keep the 15 round mag(s) in my pocket (or wherever) for higher capacity backup mag(s).
The Glock 20 (which comes stock with the 15 round mags) is 5.47" tall, so I'd expect the Glock 29 with a Glock 20 mag in it to roughly be that tall, as well.
So, stock Glock 29 is 4.4" tall (10 round mags, and 1 in chamber), and Glock 20 is 5.4" tall. An inch increase between the two.
You can also get a 4.6" aftermarket barrel for your Glock 29, if you want to. I heard from someone that Bar-Sto can make a 6" barrel for your Glock 29, if you ask 'em. Don't know yet, since I've not personally checked that out yet. I'm sure it's true though.
For the "hottest" factory ammo around that I know of, you'll most likely want to try out DoubleTap Ammunition 10mm rounds:
http://www.doubletapammo.com/php/ca...21_25&osCsid=8dbe528c19cc480dbb5ea999e06ddc5d
Don't be scared by the price, since those're premium JHP defense rounds in boxes of 50! Usually for premium defense JHP rounds, you'll see $20 for 20 rounds with the "big named" brands out there. So, DT ammo is actually a good deal.
For cheap(er) practice 10mm, check out
www.Georgia-Arms.com 10mm rounds:
In bulk (roughly $14.75 for every 50 rounds):
http://www.georgia-arms.com/index.asp?PageAction=VIEWCATS&Category=3211
Smaller packages (their 180 gr. packs of 100 FMJ practice rounds for $30; so $15 for every 50 rounds here):
http://www.georgia-arms.com/index.asp?PageAction=VIEWCATS&Category=3219
^ Georgia-Arms also have cheaper 180 gr. JHP GD 50 round packs for $20, but I don't think they load their ammo as "hot" as DoubleTap. If hiking in the woods, you want some nice hot DoubleTap 200 gr. WFNGC Beartooth rounds, for good defense against bears.
You can convert your Glock 29 to .40 S&W, 9x25 Dillon, .357 SIG, .22, 9mm, etc. All except .45 ACP. I heard someone converted their Glock 20 to .38 Super, but not sure? I never tried this.
If going Glock 29, then check out
www.GlockTalk.com
Check out their "10-Ring forum" :
http://glocktalk.com/forums/forumdi...1&pp=35&sort=lastpost&order=desc&daysprune=-1
Also, for more 10mm talk, check out:
www.10mmTalk.com