what is a multiline cell?
In trees, listboxes, etc, there is an option for Multi-line input. I think this is what the OP means. Not sure how to change the spacing though.
This it seems won't work, but I'll post anyway in case a) it will work and I just couldn't get it right, or b) someone else considers this and I can save them time...
I don't know of a way to set Line Spacing, but if you're really really wanting to do this, you could consider inserting line breaks with small spacing.
For example, if your normal font size is 15, and you want a slightly larger line break, you could try using something like:
<my text at size 15>
<empty line at size 5>
<my continued text at size 15>.
The reason this doesn't seem to work is that I can't seem to retain varying font size once I put my string into an array. If someone has a solution for that, then this could be a (n ugly) possibility.