Can I tile a 3" wide band of 1" x 2" glass tiles on a plaster bathroom wall (not in the shower area) with no modifications to the wall?
Glass tile on wallboard presents no special challenge. Glass tile on plaster is ok also, as long as it is not too uneven. You'll need trim on the top and bottom to make the transition look good.
Also as @HerrBag alludes in the comments, glass tile is harder to get right compared to opaque tile.