I just put this in VP's main.m file. Someone else might find it useful:

#ifdef DEBUG

NSWorkspace *workspace = [NSWorkspace sharedWorkspace];
NSArray *launchedApplications = [workspace launchedApplications];

for (NSDictionary *junk in launchedApplications) {
    if ([@"com.flyingmeat.VoodooPad_Pro" isEqualToString:[junk objectForKey:@"NSApplicationBundleIdentifier"]]) {
        NSLog(@"It's already running you moron");
        
        ProcessSerialNumber psn;
        psn.highLongOfPSN = [[junk objectForKey:@"NSApplicationProcessSerialNumberHigh"] intValue];
        psn.lowLongOfPSN = [[junk objectForKey:@"NSApplicationProcessSerialNumberLow"] intValue];
        SetFrontProcess( &psn );
        
        NSBeep();
        sleep(.5f); // let the beep actually happen.
        
        return 0;
    }
}
#endif