The problem with finding a cyclocross bike (at least in my experience) is that if you are 5'4", somewhere around a 30- 31 inch inseam, like I am, if you downsize to a smaller than race bike bike, you may very easily have toe overlap. If you make the triangle smaller (i.e. with a more dropped top tube, you decrease the size of the triangle and that makes it hard to get your arm easily through the triangle when carrying and sometimes you need to modify your carrying style to hold onto the bottom of the downtube, etc.

I did not really find as much problem with less top tube clearance like I do with a mountain bike, because when I am dismounting off my cyclocross I am swinging my leg off the bike and not coming down directly onto the top tube before dismounting, thus less need for top tube clearance.

I just sold my cyclocross bike to my sister in law, but I rode a 50 Redline frame. It had toe overlap at a 50; so I can't imagine what the 48 Redlines are like?