I have a cross bike and was thinking about getting a Nitto M12 front rack and a Nigel Smythe and Sons Little Loafer from Rivendell to go with it. It would be nice every once in awhile to do some day long rides and bring extra food and clothing along. I like the way the front rack looks and the ability to quickly remove the rack. My question is whether you think this might adversely affect the handling of my cross bike as it wasn't designed to carry any front load. The bag is pretty small so I won't be putting all that much into it, but it will be cantilevered out over the front wheel.

Depends on your personal preferences, and the geometry of your particular bike.

This is not such a big bag, and moderately loaded it should not have a huge effect on handling. I've got this rack on my Quickbeam, and with reasonable loads (~5 lbs.) it has a very small effect on handling.

I've also used the Boxy bag with dedicated Nitto holder off the handlebar, and not been too thrilled with effect on handling, especially descending on wet roads. The weight was too high, and cantilevered too far off the steering axis. With the M12 rack and Smythe bag the weight will be much lower and closer to the steering axis. Only one way to find out. If you don't like it, the resale prospects of this gear should be pretty good.

Bike designed for front loads will handle them very well. Adding a front load to a bike not designed for it will likely have an effect on the handling. You probably won't be able to ride no-handed very well. But, with a small load, you should be able to manage without much difficulty. Best thing is to give it a try and find out. Just keep your loads light. If you find it annoying, then consider a rear rack

The purpose of the rack is to carry the load on the fork instead of the handlebar. So, it will be more stable than the same bike with a handlebar bag. However, whether it will be more or less stable than the same bike with NO front end load will depend on the bike's geometry. Given the small load that most folks carry, there is generally no great difference either way.

Disclaimer: I sell these racks (and use them all the time, too!).