Hi Nobbie,
Rather than try to compromise you might be better off with 2 bags.
I too have done the cross country, hockey, lacrosse, basketball with my kids, and have now started to travel a bit.

I have a shoulder bag F-4AF which was fine for one camera and the original 70-200 zoom a few years back. [url]http://www.tiffen.com/displayproduct.html?tablename=domke&itemnum=700-40N[/url]

Now the 70-200 is a bit bigger and I shoot with two cameras, one wide angle with hood, the other telephoto with hood. I have dumped all the inserts and both cameras drop into the J-1.. [url]http://www.tiffen.com/displayproduct.html?tablename=domke&itemnum=700-J1B[/url] bag, set up and ready to go.

Sooner or later you will probably need a bag about the size of J-1, especially if you upgrade any gear. Better to have a little spare room rather than not enough.

If you are in USA, Photoplus expo, on east (October 23-25 NYC) and west coast I think, is a good place to hands-on compare equipment. Or order from a reputable place like B&H for an easy return and exchange policy if need be.

Good luck
Paul