In the 'old days' (ie about 10 years ago) the answer would have been rope lights with incandescent bulbs. Infinitely dim able!
Now, you can get LED strings with multi-color LEDs so you can pick your color. Most of these are about 3/8" wide x 16' long, with a peel-off strip on the sticky back.
Search for >LED strip mounting channel<. There are varieties at 45* angle, a U-channel to embed in drywall (fill in that decorative expansion joint), and curved strips to gracefully light the wall. Most are aluminum; some have clear or translucent covers strips.