Split mats work great. Just about every OK tournament we've ever been to ran the younger kids that way. A small mat may just be split in half but a larger mat may actualy be split in fourths.
There are a few small things that could speed up tournaments by keeping the mats moving (these are my experiences from the South)...
1) you can't double enter in the same division - I know parents are just wanting to get little Johnny more mat time (or more ribbons) but a lot of the time the weights end up combined anyway so the kids ends up wrestling eachother 2x. The rules cover this but it's not enforced. If a kids wants to wrestle up a division that's fine, and I would encourage it. (Open Tournament Rules #3)
2) the 15 min rest does not apply for matches in seperate divisions, only matches in the same bracket. Again, covered in the rules but not enforced. (General Rules #11)
3) A wrestler gets 2 mins to report to the mat (after the 1st match of the day) or the match is forfeited. (General Rules #10)
Wrestlers (or parents) not paying attention to the mats or other "excuses" take up a lot of time. A minute here and there all day long adds up. Make a kid forfeit and I promise next time he'll be paying attention.
OK usually ran the bout numbers 2 or 3 ahead so they had time to page a kid before he was up.
Also, having the winner sign the bout sheet always shut up a lot of arguments later about the outcome of a match being recorded wrong (I only throw this out because this happened at the last South tournament). It only takes 2 seconds.
I would also like to see the wall brackets get updated during a tournament. It's not a big deal with round-robin brackets but parents seem to get so confused with double elimination brackets. I don't understand the confusion - my 7 yr old can figure it out but apparently it's a mystery to some. In that same vein - winners should get the wall bracket. My son still has all his brackets from OK (of course, they were a little more professional looking then most of the Xerox copies used around here for the wall). Also, I like being able to buy brackets but most tournaments (at least in South) don't have them.
One more thing - I think that the Novice rule should include an exclusion for kids that have done any sort of grappling before (not just wrestling). I'm tired of seeing true Rookie & Novice wrestlers getting slammed around by experinced Judo or Jiu Jitsu kids. Both of my boys are Open wrestlers, so this isn't because my little Johnny is getting his butt kicked. I also like how OK handles it - once a kid places at so many tournaments with X or more kids in the bracket he is no longer eligible to wrestle novice.