Up first is the old stem (gooseneck) that magically fit the hole on my Monark Thunderbird. It's minimum insertion point is in lower than the original post that came with the bike. The seat clamp bolt goes through a piece of pipe that's shimmed and fit inside a bigger piece of pipe that is clamped in where the handlebars would normally be clamped.
Next is a custom made piece by Chad at Chop Shop Customs. I measured the angle of the seat tube to get the layback portion as close to level as possible.
And here's one I got off eBay, supposedly for motorized bicycles. It's similar to Cap'n Awesome's but with a bit of a gusset.