after using a noisy and heavy Truvativ chain guide, I'm wondering which of those wonderful products out there offer a similar service without the heft, if you dig me. I don't need ti to be espeicially effective: I'm not bombing down hills or huge drop offs, but I hate losing my chain, and I find without one it can go walkies merely coming off a curb

ideas? I'd preferably like to keep the cost down

thecheapo dmr chainguides are quite light.

but of course if you go light and cheap you loose strong...

the other solution is to use a front mech as a chain guide...

I'm with Mark here - a front mech should normally keep your chain in place.

It might be worth shortening the chain by a couple of links as well if you haven't already done it.

indeed, it should possible to keep a chain on a single ring without a chain device.

when in the largest cog at the back it wants to be pussling the arm on the rear mech almost to the limit of it's spring.

if you are still losing the chain then stick a front mech on it and use the adjusters and a bit of cable to align it (I'll leave you to work out how!).

other possibility is the forge chain tensioner, it small and simple...

I'm using a shiort cage mech: will tightening the chain to the max keep the chain in place?

The Roox Chain Dog seems to be the weapon of choice, but it's a fortune for a diddy piece of kit

This is what you need:-
http://www.forge-mtb.com/chain.asp?cat=FORGEMTB&catalog=FORGEMTBP