Ideas for themed rounds - let's see. From the list of themes that have been suggested in the past, but never used, here's what I like, and the reasons why.
Civil War - this is a great one - covers lots of periods, allows for an easy way to have two opposing sides in the entry, and can be interpreted in some interesting ways, probably.
Creatures - I like this one a lot. You could have two opposing gangs of creatures, or a gang of creatures and a gang of hunters. A good opportunity to paint fur/scales/hide too. Could be fun!
Hats - a nice whimsical theme.
HQ group - HQ groups are often the ones that army painters give more time and attention, which would be perfect for the LPL, which has at its heart the idea that it's a good way to reduce the lead mountain.
Literature - we did movies last year, so why not literature this year? Plus, I teach literature, so I have to throw my hat in the ring for this one.
Mercenaries - my favourite, I think. LOTS of scope - many different periods are possible with it, too, which I think is important for LPL.
Cops and Robbers - what's not to like?
Looking forward to seeing what rounds we get!