I have one 6x12. Bought it 5 Sep. I've done one event, Sep 21, it went pretty good for first time solo. Had a line a few times but with the band right next door I don't think anybody minded the wait. Some pics of the trailer are at:
http://dimensional.com/~zeb/bbqtrlr/In pic2 on top of the frige to the right is where the brisket is cut coming from the CS150 on the left. Propane steam table is in middle of pic.
in pic3 first on the left is sink, water storage, 12v car battery for water pump and propane water heater below service table at window, steam table, frige. CS is on right.
Bread and buns and other stuff storage overhead. Waste water tank is below floor of sink.
7.5x10, you could put the sink setup on the right. Save room for 4-6 coolers for drinks.
Keep me posted,
Lamar