Commuting - building a commuter (recs needed)

I am building for a friend a commuter bike out of an old chromo Rockhopper frame. This is mostly using spare parts out of my basement, but I need drivetrain recommendations. So far here is what I have:
-Rockhopper Frame and 1 in threaded rigid fork (both to be powdercoated)
-Old 7 speed 26in wheels (Araya rims and Alivio hubs)
-New GEAX 26x1.6 Street Runner tires
-Old Acera RD
-New 7 sp Altus Cassette
-New Sram 7sp grip shifter
-New cheap Kalloy mtb riser.
-Old v-brakes of various makes.
-Old and very heavy bb and crank arms.

My question is what is the best way to run a single ring in the front? 7 speeds will be enough and I'd rather not throw on a triple and fd which will never be used. I am worried that the chain will keep bouncing off. Any help would be appreciated. Any other recommendations that make for a good solid commuter for use in the city of Chicago would be great too. Lights and locks she will get herself. Thanks

My question is what is the best way to run a single ring in the front? 7 speeds will be enough and I'd rather not throw on a triple and fd which will never be used. I am worried that the chain will keep bouncing off. Any help would be appreciated. Any other recommendations that make for a good solid commuter for use in the city of Chicago would be great too. Lights and locks she will get herself. Thanks

I have a single ring up front. In lieu of purchasing shorter chainring bolts I threw on a bash guard from BBG ($10 + S/H on eBay).

I guess I would take the FD and granny off and use the middle chainring position (most likely best chainline) and use one of the following options:

(1) keep the big chainring on as a bolt spacer/sacrificial-bash-guard
(2) get a bash guard (usually matched to middle ring size but not necessary, offers a cleaner look than (1) )
(3) get shorter chainring bolts and keep one ring on...

good luck!

If you are going to run a single up front, keep the inside and outside covered. testtube's recommendation of a bash guard is a good one, but I also run a ChainWatcher (http://www.rei.com/product/9610812.htm) on the seat tube. I'm not the type that likes damaging my frame and getting off in traffic to yank out a bound chain . . . but that might just be me.

I have a single ring up front. In lieu of purchasing shorter chainring bolts I threw on a bash guard from BBG ($10 + S/H on eBay).
Hey, would you be able to link to the exact auction? I keep searching for this but keep finding only ultra-burly bash guards made from unobtanium and designed for gnarly DHers. Sorry, maybe I am being dim with my searches.

Hey, would you be able to link to the exact auction? I keep searching for this but keep finding only ultra-burly bash guards made from unobtanium and designed for gnarly DHers. Sorry, maybe I am being dim with my searches.

This is their website (http://www.bbgbashguard.com/) and here is an eBay search for "BBG" in Sporting Goods > Cycling (http://sporting-goods.search.ebay.com/bbg_Cycling_W0QQcatrefZC12QQfromZR10QQfrppZ50QQfsooZ1QQfsopZ1QQftrtZ1QQftrvZ1QQmaxrecordsreturnedZ30 0QQsabfmtsZ1QQsacatZ7294QQsaobfmtsZinsifQQsaprchiZQQsaprcloZ)

I bought mine off eBay. It was shipped quickly and i'm happy with it. If would assume you can get what you need from their website if they don't have an auction for a size you want. It looks like the prices are the same between their website and eBay.

How about putting an old front derailleur on it? That'll keep the chain on. Just don't hook it up to anything.