Ok, well I came up with something. It's entirely labor intensive. I don't know if there might be some fancy way to do it with an extension or something else. But this is what I've got.
1 - Set up a pixel grid (that means grid lines 1 px apart for both x and y direction)
2 - Set up snapping (snap to cusp/corner nodes and to smooth nodes, and also snap to grid)
3 - Pen/Bezier tool
4 - Make first triangle something like 410 pixels tall, 20 px wide. The Pen will automatically place nodes at the grid intersections. (It could be 510 or 510 or 310, but the 10 is important, you'll see why when you're almost finished)
5 - Switch to the Node tool
6 - Duplicate the triangle
7 - Grab the top-right node and drag it out to the right by 1 grid line and down by 1 grid line (it should automatically snap to the intersection)
8 - Grab the top-left node and drag it out to the left by 1 grid line and down 1 grid line
9 - Grab the bottom node, and move it straight up by 1 grid line
10 - Repeat 6, 7, 8, 9 and 10 until it's finished