Is there a plugin API for Ollydbg to execute, say, 10 instructions, then break?

use ollyScript instead of searching for particular plugin

Latest Ollyscript can be called from any plugin

well to execute 10 instruction and break use
ctrl+t --> check mark command count is box enter the number of commands you want to trace and break viz 10
hit ok and use trace in ctrl+f11 olly will stop on the 10th command
that is executed

and would say some thing like

Log data, item 0
Address=0040100C
Message=Conditional pause: 3. commands traced

Arjuns, thank you. I had seen the ollyscript forum before but didn't pay it much attention because I never thought it would be what it is. Oh me anon, I didn't know you could even do it that way in regular ollydbg. Thanks for the tip, although I think I'll be using ollyscript.