I did a search and found this thread: https://ogrforum.ogaugerr.com/...like-brands-of-track
Looks like ACE made a custom O gauge crossover. It would be easy to modify this for O and Standard gauge. I don't have a radial arm saw, so I'll need to be creative on how to mill the junction. It looks like it would work well and solve my problem. My other minor problem is that two loops of O and two loops of Standard is a lot of track and may constrain my space for accessories. I'll update this thread as I make progress. It might be a while given the time involved in prepping the space.
George