What are some designs for "safe" melon farms?

I really like the wheat farms described in this answer, because it's impossible to trample farmland and harvested crops always bounce back at you.

Are there any similar designs optimized for melon farming?

I tried putting blocks directly above where melons grow, but then I can't get any slices that fall back to where the stem is.

Solution 1:

I place a glass block directly over the stem. This ensures light gets through but I don't squish my melon seeds.

Solution 2:

You can build a fully automatic melon farm by using stick pistons and regular pistons.

The only downside is that it's quite large per-melon, but since it's fully automatic, I think the downside is easy enough to cope with.

Solution 3:

Build a melon farm according to a design that means each melon can only grow in one place:

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Since you have to re-hoe after harvesting a melon anyway, this design means there's no difference in the amount of hoeing that needs to be done.