I'm not sure I understand what you mean. Could you produce an example of what this might look like?

kelvSYC wrote:

We currently have markup like this:

• foo
• bar

However, when we have a very long list (and the length of each item is
reasonably short), it would be a presentational disaster to just leave them like
that, as we waste lots of whitespace. The idea is to introduce perhaps another
kind of wiki markup that would allow lists to be formatted as inline-block to
take advantage of that wasted space without using HTML (see for example
[[b:Wikibooks Pokédex:Alphabetical Index]], where ugly HTML and CSS float-hacks
are used).

Ideally, this new list would be exactly identical to our old list, except that
the new list has display:inline-block rather than display:list-item.

So, assuming a % was our wiki inline-block list marker, a list like this

% foo
% bar

would look like this:

• foo *bar

rather than

• foo
• bar

Going through old bugs... I'm going to go ahead and close this out as this is a CSS styling issue, and doesn't require any built-in support or syntax.

Some templates also invoke CSS multi-column support for a similar effect.