Personally I think the terrain would factor in a lot more. If the fight were in an open, flat field, then the channeler would probably be able to nuke the mistborn before they came within 100 feet (I think of it as Mistborn=ninja, and channeler=mage)
But if it were in a small space, then most likely the mistborn would be able to kill the channeler before they could weave anything, using coins and such. Also, a city fight would figure a lot into the mistborn's favor, as there would be tons of pushing and pulling anchors to use, probably enough for the mistborn to stay consistently out of the channeler's sight and crosshairs. you can't channel at what you can't see.
of course, there are things like if the channeler has wards or has time to make big fancy traps, but I think that a good pull on a peasant's coin pouch behind the guy (or just a nail for that matter) would be enough to kill most channelers, especially if you have them distracted.
This is assuming that no one fights an allomancer long enough to figure out some freaky weave to shield them. they'd have to block the energy within the allomancer's body, rather than try to break them off from the source. (obviously, if they haven't fought them before, they'd assume that they fought using the source, and try to shield them while the mistborn stabs them in the face.) that'd take way too long to figure out, even for the main, prodigy characters.
Besides, if the fight was in the mistborn world, then the channelers can't even use their magic because the Power is not there to use.