I needed this for the grades I am making to the resume edition and I thought I would share it here. It is a simple macro that lets lists the output of a filter in multiple columns.
You use it like this:
<<multicolumnlist "[tag[foo]]' 4>>
and it will list tiddlers tagged with `foo` split into 4 columns. It is filled row-by-row and I haven't added styling options yet because I just realized I should do that as I am typing this. So later today there will probably be styling options.
Here is the macro stuff on my site:
http://inmysocks.tiddlyspot.com/#Multi-column%20List