I tend to output as much information as I can in a single broadcast.
It's possible you could develop your own chat-within-chat by storing every chat entry through macros as a variable, and every time someone adds anything, it gets added to your stored variable and reposted:
[macro]
Hi
[output]
Chris: Hi[macro]
This is Chris
[output]
Chris: Hi
This is Chris[macro]
Hi Chris, my name is Bob!
[output]
Chris: Hi
This is Chris
Bob: Hi Chris, my name is Bob!Using this method you'd have to re-post the entire "chat log" every time you add something to it, to eliminate the white-space problem. You could also remove any entries older than say, 20 posts long so it doesn't get overly huge. It won't make much sense scrolling back through, but I can't think of any other solution of which I could theorise.
Through
Wiki: broadcast() and html you can control background colours of tables, to eliminate most of the white space.