[suicideneil]

Motor sizes vary- typically though, 1/8 motors are atleast 74mm long; XL sized. Diameters also vary but 36mm is pretty standard for 1/10-1/8 motors ( not including fins ). Alot of the beefier 4 pole motors are more like 39mm diameter- for your pirate, take a look at the castlecreations MMM motors like the 1515 and 1518- will depend on the voltage and speed you are aiming for.

I beleive your motor mount issue has been answered- you will probably have to either customise one of Mike's mounts, or make your own using some 3-5mm thick 6061 T6 aluminium angle...