How to create Mac OS X global hot key to open .txt file in MacVim.app at vim 'mark'?
Two possibilities are Keyboard Maestro or Alfred. Keyboard Maestro will set a global keyboard shortcut.

I assume there is a command-line utility for MacVim like there is for BBEdit and if it can open at a specific ‘vim mark’. For example, BBEdit’s command is called bbedit and cal open a specific line number using “:xy” where “xy” is the line number. You could make a Keyboard Maestro shortcut that will open a specific file using this command

/usr/local/bin/bbedit /path/to/filename:33